It's been two years, whoever's "fault" it is, it hasn't been resolved.

Take even the least charitable view: you've been misreading the situation and this person objectively isn't toxic. If others at the team get along with this person, or shrug it off, then it's a sign the team isn't for you.

In either case, the manager makes a choice in their non-action with the 'toxic' teammate. So if anything, the manager is mostly covering up for their own poor management that will come out when you leave the team.

Life is short, frankly you don't owe anyone anything, make the choice that's best for you