thanks for that
I don't know if that means you're convinced or not, but here's some other good points:
1. Bouyancy is 100% only an upward force, so if we assume gravity doesn't exist, then you're still lacking an explanation for why things are pushed down.
2. Go to different places on the Earth with sensitive scales and you'll find that the downward force (of gravity) is different. This is true even if you measure at places with the same air pressure and same elevation. How is this possible if you aren't changing anything about the density of the air? Note that gravity perfectly explains this because you can move around the planet and change how the mass of the Earth is distributed relative to you.
3. Private companies (ones unaffiliated with governments/NASA/whatever) have flown planes with sensitive gravity-measuring equipment in order to map how gravitational acceleration changes over the landscape. They do this to look for minerals, natural gas, and oil because flying over a massive deposit of oil means there's a whole bunch of space under you which would normally be rock, but is instead a much less dense material with less mass. Thus, you measure gravity to be less at that point. This is called exploratory geophysics.
https://csegrecorder.com/articles/view/magnetic-and-gravity-methods-in-mineral-exploration
