RPGMemes

Yeah, the fact that revivify targets "a creature" is... really weird. It's probably one of those situations where WotC wrote something inconsistent with the rest of their rulings and metaphysics (a corpse is never a creature, so under super strict RAW revivify can never actually do anything) - and rather than errata it to "the corpse of a creature" they're just behaving like the wording is intentional.

For most purposes, it's pretty obvious how it's intended to work, so it's sort of fine. But it irks me all the same.

I think there's a difference between the philosophical concept of "you" (which for me means the holistic construct of your body, your soul, and your experiences and thoughts and personality) and "your corpse" (which for me means a sack of meat and bones.) - different people might differ on this though.

Sage Advice has some tangential stuff on whether or not a summon you create counts as "you" doing something that might be helpful for whether summon planar ally (or summon celestial etc) counts as "you" doing something - specifically they've said that if you cast a spell like "summon celestial" and it goes and attacks someone, that doesn't break an ongoing sanctuary spell on you, even though it's using your spell attack modifier. I'm not sure I super agree with Crawford on this point in the wider sense (he said that spirit guardians wouldn't break sanctuary!!!) - but it's an interesting data point on what counts as "stuff you do"

In general, my recommendation with any of this stuff is to talk to your DM, because the metaphysics of 5e aren't really explicit enough for anyone to predict how their DM interprets them, and this idea is flangy enough that you're gonna want to talk it over before trying it :)