Are the "muddled thoughts" from Synaptic Static a magical effect?

Question

From the description of synaptic static (XGtE, p. 167; emphasis mine):

You choose a point within range and cause psychic energy to explode there. Each creature in a 20-foot-radius sphere centered on that point must make an Intelligence saving throw. A creature with an Intelligence score of 2 or lower can’t be affected by this spell. A target takes 8d6 psychic damage on a failed save, or half as much damage on a successful one.

After a failed save, a target has muddled thoughts for 1 minute. During that time, it rolls a d6 and subtracts the number rolled from all its attack rolls and ability checks, as well as its Constitution saving throws to maintain concentration. The target can make an Intelligence saving throw at the end of each of its turns, ending the effect on itself on a success.

Can this condition be removed with Dispel Magic?

Does "Magic Resistance" (advantage on saving throws against spells and other magical effects.) gives you advantage against INT saves to remove this effect?

It seems more like a concussion rather than a magical effect from a spell.

Answer 1

Dispel magic would not get rid of the effects of synaptic static.

Dispel magic ends spells (as opposed to magical effects in general):

Any spell of 3rd level or lower on the target ends [...]

Synaptic static's duration is instantaneous, however; the spell has already ended by the time the effect it produces could be dispelled, so attempting to end it does nothing, much like with animate dead. Dispel magic would only work if the spell's duration was tied to the length of the effect, like in blindness/deafness' case.

Magic Resistance also would not work on the lingering effect (though it would apply to the initial save, as that's part of the spell itself). From the Sage Advice Compendium:

Can you use dispel magic on the creations of a spell like animate dead or affect those creations with antimagic field? Whenever you wonder whether a spell’s effects can be dispelled or suspended, you need to answer one question: is the spell’s duration instantaneous? If the answer is yes, there is nothing to dispel or suspend. Here’s why: the effects of an instantaneous spell are brought into being by magic, but the effects aren’t sustained by magic (see PH, 203).

Synaptic static being an instantaneous spell is one of these cases where its lingering effect is not sustained by magic, and is therefore not under the umbrella of being a 'magical effect'. If even an antimagic field (which suppresses magical effects) would not suppress the lingering effect of synaptic static, then Magic Resistance is no help either.