I need help calculating min/max damage possible with this character

Question

I'm posting a link to the character's sheet because I'm not even sure I got all the attack options and damage additions I have or what order they need to go in to get the maximum possible damage out of the character below. I just need to know know what the best attack order is and how much the minimum/average/maximum damage will be for the very first round when I have won the initiative roll to have advantage from attack an enemy that has not taken a turn in combat yet. Then what the subsequent rounds of damage would look like after using all the one-time use options have been used such as spell slots and daily reset abilities.

This build is not for legal play or for play in campaign. It is a character that is being built for a PvP tournament that players are putting on at a local game store. There are 30 people so far who signed up. The edits to the weapons showing the added potion of giant was just a way for me to try and keep track of all the added damage needed in my failed attempt to try and get the answers I'm looking for.

The parameters are that:

1. any class, Item, Race, Background, Subclass, and spells that are available options on DnD beyonds character creator with all the Sources, Partnered content, and optional feats from every available book they have.
2. You can have a total of 15 feats from all sources (but all the feats that do the same things just worded different like two-weapon fighting count as one so you get all the benefits from what the skill should be able to do).
3. You get all the expert skill feats you want to take.
4. You can be attuned to only 6 items maximum.
5. No limit on the amount of magic items you can have that do not require attunement.
6. Ay weapon you choose can be made into a +3 weapon if it is not already one.
7. You can use a maximum of 25 tomes that Raise your Attributes.
8. You can take any potion and apply any poison or activate any item that requires an action or bonus action to activate, before rolling for initiative, but can not cast any spells or abilities or start the match invisible.
9. You have to roll for starting stats (3 sets rolling a d20 6 times re-rolling any 1-9 rolls keeping only 10-20’s rolls).
10. Have to take average health.
11. Combat and gameplay rules from official sources will be used for play.

The things not allowed are:

1. No personally created Races, Feats, subclasss, Items, Spells, or rules are allowed.
2. no wish spells, unlimited summons, infinite loop, or builds that create multiple copies of yourself or a summon.
3. no greater invisibility Spells, Items, or Potions.
4. No spell scrolls before or during the match.
5. No Epic boons.

It will be one one-on-one to-the-death elimination style play. Drawing from a hat to determine the matchups. In a different custom arena for each Elimination round of play, so you never play in the same arena twice.

I think I have a good build to do a pretty decent job in the tournament with a good chance for massive damage but also a good bit of ability to mitigate and handle damage.

Link to PDF of Character Sheet

Link to DnD Beyond character Sheet if You Don't Want to Download the PDF Version

I have chosen High Elf, Fighter champion 5, Ranger gloom stalker 3, and Rouge Assassin 12

Stats- Str 30, Dex 30, Con 30, Int 10, Wis 30, Cha 10, Proficiency 7.

Feats- Elven accuracy, Piercer, Metamagic Adept (quickened spell & empowered spell), Poisoner (for the poison resistance ignore since we can apply and drink potions out of combat prior to the match starting except for greater invisibility), Dual wielder, Two weapon fighting style, Twin weapon fighting master, Twin wielder, Duel expertise, Attunement master, K.i.s.s Master, Martial Adept (Menacing Attack, Precision Attack), Explosive Crit, Savage attacker, Squire of Solamnia (background feat),

Items- Blood Fury Tattoo, Ioun Stone of Mastery, Red Wizard Blade +3 (Oil of Sharpness) Bloodshed Rapier +3 (oil of sharpness).

Potions & poisons- Purple Worm Poison (Both Weapons), Potion of Heroism, Potion of Giant Size, Potion of Speed.

Spells- Booming Blade, Gilver's Wind Blade Roulette (1d10+10 to six targets) or (6d10+[60 or 10 I'm not sure how the +damage works when it only targets one enemy instead of 6] to 1 target, 1 action, 1 spell slot level 1), Hunters Mark.

Answer 1

I don't think your question is directly answerable. We don't know the parameters of your challenge, and that character's kinda complicated. Rather than vote to close, I'm going to try to answer your question more broadly.

You should also understand that character breaks sooo many rules. There's nothing wrong with that, people make homebrew games all the time that break the rules, but it does make it pretty difficult for strangers on the internet to provide much help.

As an example, about Attributes, the Basic Rules say (emphasis added):

A score of 10 or 11 is the normal human average, but adventurers and many monsters are a cut above average in most abilities. A score of 18 is the highest that a person usually reaches. Adventurers can have scores as high as 20, and monsters and divine beings can have scores as high as 30.

And, of course, your character has four 30s.

Seek help from the DM, or other players

You say:

I am very new to dnd

The character you present is completely over the top. There's nothing wrong with that, but at first reading it's hard to believe that you've understood the parameters of the challenge.

That is a massively complicated character, it needs review

As a tiny example, there seems to be the description of a potion of giant size in the notes of your bloodshield rapier.

As another example, why not 30 in intelligence and charisma as well?

Review the rules, in detail

If you're engaging in a 20th level PvP tournament, you need to understand the rules, completely. At a guess, most of the people you'll be playing with will be.

Practice

If there's someone you can practice with ahead of time, that might help. Just two of you can walk it through.

Consider a different option

The challenge you're referring to compares to D&D the way playing chess with, oh, 5 extra queens compares to regular chess. Or playing poker with two decks mixed together.

There's nothing wrong with that. Play D&D however you want to play, but you should understand that is a very specialized form of D&D, and bears as much resemblance to "real D&D" as the chess and poker I mentioned compares to the "real" rules for those games.

Maybe the game store has some options for new players. My best recommendation is to start playing D&D with simple level 1 characters and a simple adventure. Maybe that sounds boring compared to a 20th level PvP tournament, but really it isn't. It's a great game, and it's worth learning from the beginning.