> If you open a new bank account and deposit a lot of money, say over $10,000, then they almost certainly will freeze your account
I have done this multiple times with zero issues whatsoever. With larger sums than $10k, and with global-sized banks. Sorry to hear about your issues but you're over-extrapolating.
> I open (and close) a lot of bank accounts to collect those signup bonuses
This, I think, may be your issue. For one thing, as the recent NYT piece on customer scores shows, these companies do exchange information on their customers- you may come up flagged or even blacklisted specifically because of this
https://money.cnn.com/2014/05/07/pf/bank-account-closing/
I once had a bank account closed for "suspicious behavior." The suspicious behavior was making too many transfers to one of my other bank accounts.
If you open a new bank account and deposit a lot of money, say over $10,000, then they almost certainly will freeze your account and you'll have to call up to unfreeze it. Sometimes you even have to go to a branch to unfreeze it.
Chase, specifically, is really bad when you're trying to transfer to/from new accounts
https://www.doctorofcredit.com/psa-dont-use-ach-pull-for-cha...
I open (and close) a lot of bank accounts to collect those signup bonuses. If you read forums dedicated to this then you hear stories of people getting their bank accounts terminated suddenly for opaque reasons all the time.