That would explain why the normal Celeste Classic felt so weird to play after doing Foreverred Trueskip. I definitely prefer the consistency of Foreverred, especially since it allows for even more difficult levels. Though, with the exclusion of Etherealization, it becomes that both Trueskips are technically easier than Gemskip in base Celeste Classic.
Also, I did end up buying the full Celeste on Steam. Apparently, the Farewell chapter is only considered "red intermediate" difficulty, so I have a long way to go.