It's only in the promotions inbox, which if Gmail is sorting correctly is just full of commercial spam anyways. Doesn't really impact the experience for me since I rarely ever check it
They definitely started putting them in all inboxes for the mobile app, I turned off the split inboxes when it happened, could have been A/B testing or something like that.
I looked at degoogling myself straight after that, spent hours reading and planning and looking through options, then realized that any solution options would not work for the rest of my family and now just stare into the pit of despair that is our dystopian reality.
Might check out how proton is doing now though.