Ok. Are all Lex Luthors evil in every timeline except for Injustice?

That is another case where Injustice wasn't exactly new either. There have been several inverted cases of a then good Lex Luthor. Especially in worlds where Superman is the opposite.

Ok.

I wonder, was "A Better World" the first example of the League becoming evil in an alternate timeline, as opposed to something like Crime Syndicate where they were villains from the start? I guess you could consider Kingdom Come (not quite evil) and the Squadron Supreme mini before that (not quite the Justice League) as precursors to the Justice Lords/Injustice concept.

I meant to say Injustice had similar details with that episode.

Yeah, I do believe Better World was the first time it was a 180 later on that wasn't caused by mind control or another villain's influence of some kind.

Hank Hall as Monarch and Extant and Hal Jordan as Parallax had no influence originally. Those were just retcons. "Hero turned evil in the future" was the basic plot of Armageddon 2001 and many others followed. By now probably every major hero has had a dystopian dictator elseworld or future.

Would Superman and anyone who followed him redeem themselves at some point in the future?

True, I guess without the retcons, those counted on an individual basis. Not for the whole team though.

Also some already did. Flash did in the first game's events, and Hal Jordan ironically was the one to do so in Injustice 2. Along with Shazam being the case to switch sides and immediately die.

I felt so bad for Shazam…