I have the same problem on all types of proxies (I am using everything, residential, data center, mobile, real mobile, real residential). So I really don't think it has anything to do with proxies. Every once in a while I can fix a follow block, but it usually comes back pretty quick.
All everyone talks about it proxies but I have been testing different proxies for over a month now and there is no difference in behavior between proxy type. This is something else.
I also create accounts, and was testing some new methods. Bought a brand new phone, used it on a mobile IP in a huge city with a cell tower (subnet) I have never used before, a clean email address. Instagram blocked the phone from making an account, like they can read my mind! Of course, I am sure it was something else their AI detected... perhaps not enough contacts in the phone, maybe they android is being flagged in general (no problems making account on iPhone) or not enough apps downloaded, or the phone was a cheap model, who knows. But the fact is Instagram is just SO good at detecting any manipulation now that our jobs have become 100 times harder.