Can 2 non-cantrip-spells be cast in one round with action surge?

Question

Fighters have an ability that allows them to take 2 actions in one turn (regular, full, unrestricted actions, unlike those gained from the Haste spell):

Starting at 2nd level, you can push yourself beyond your normal limits for a moment. On your turn, you can take one additional action on top of your regular action and a possible bonus action.

Spells with a casting time of one bonus action have the following restriction:

A spell cast with a bonus action is especially swift. You must use a bonus action on your turn to cast the spell, provided that you haven’t already taken a bonus action this turn. You can’t cast another spell during the same turn, except for a cantrip with a casting time of 1 action.

Now, this creates some logical conflict.
As far as I can tell, RAW would allow you to cast 2 any-level spells and one cantrip as a bonus action (if you have one - only Magic Stone and Shillelagh fall into that category).
However, if you were to cast a spell of level 1 or higher as a bonus action, you could not cast any non-cantrip spells with any of your two actions.

This does not make sense at all from a logical point of view (considering "a spell cast with a bonus action is especially swift"). Now while I wouldn't allow casting bonus-action spells with your actions (which is explicitly ruled out - see quote #2), I don't think that the scenario above makes sense.

Are there any passages in the PHB that clarify this issue which I missed? And if there aren't, have there been any developer rulings on this topics?

Addition: If I were to cast a level 1+ spell with a bonus action, could I then use the action granted from Action Surge to cast a non-cantrip spell? RAW, no, but I feel like this ability wasn't taken into account when the rule was created.

Answer 1

Yes.

You have already quoted the relevant rule. The only restriction on casting multiple spells in a turn is found in the section for casting spells as Bonus Actions. Therefore, the absence of any other restrictions allows a fighter to cast one spell with their Action and another spell with the Action granted by Action Surge.

Note the tweets from Jeremy Crawford:

@JeremyECrawford Forgive me Sir, can you the action surge be used to cast another spell during the same turn one has already been cast?
@Mynock74 Yes, Action Surge can be used to do anything an action can normally do.

@JeremyECrawford Thank you. I guess I was wrong. I thought normally you could only cast a bonus and cantrip during same turn.
@Mynock74 That's the rule when you cast a spell that has a casting time of "1 bonus action."

Note that sorcerers can quicken their cantrips, which provides them with more options, and is likely the reason for the restriction in the first place.

By RAW, if you cast a cantrip (or any spell) as a bonus action, you are still limited to casting only cantrips for the entire turn, while as long as you don't cast a bonus action spell you can cast as many of any type of spell as you are able. Note that this also applies to using your reaction on your turn, such as conutering a counterspell against your original spell. Many tables will find the rule to be incongruous and might modify it.