So the entire case here is "Variant lineage with a feat with a +1 ASI is OP".
Which, yes. There is one single OP race in Tasha's. Meanwhile Fey Touched isn't notably better than whichever is relevant of Observant, Actor, or Keen Mind (all from the PHB). I've seen Observant save the party and change the tone of the adventure with a wisdom class, and I've seen Keen Mind save an entire adventure. (Honestly I rate Telekinetic over Fey Touched). Actor is the weakest of the three in the PHB but is fun and works really well for a whole lot of charisma classes and in the right campaign - and if you aren't playing a charisma class you don't take actor.
There are no S tier feats in Tasha's. Nothing to remotely match Lucky, Polearm Master, Great Weapon Fighter, Sharpshooter, or Bountiful Luck from Xanathar's. There are plenty of A-tier feats - and yes Skill Expert >> Skilled, but that's because skilled is a bad feat. A solid but not S tier feat making something terrible obsolete isn't power creep; it's just not junk.
As for the races, again I don't see much power creep with the one single exception of variant lineage. Yes, a Tasha's mountain dwarf wizard > a PHB mountain dwarf wizard. But I remain unconvinced that a Tasha's mountain dwarf wizard > a PHB Variant Human wizard. Tasha's boosted the weak options without touching the strong ones, and the mountain dwarf wizard is pretty much the most extreme case of boosting options that used to be off-race.
I'm curious how you think it's possible, using your definition of power creep, it's possible to have a splatbook at all with options that are neither power creep nor a waste. To me it's entirely possible and Tasha's succeeds for everything except the Custom Lineage that wasn't already underpowered.