They won't outright ban it but they'll try to de facto ban it with regulations,  or maybe they will get some ridiculous law passed. They'll try many stupid things out of desperation and fail miserably.

jgbtc

bitcoin

Strike Adopts Transfer of Funds Regulation

How would they ban self custody completely? Like they banned torrents? Like they banned privacy - they can't. 

Just as torrenting continues despite legal restrictions, and self-custody to self-custody transactions remain outside current government regulations, a complete ban on self-custody would be practically unenforceable. Self-custody is essentially knowledge of specific words arranged in a specific order - you would need to ban code and free speech  itself to ban self-custody.

You cannot ban a borderless network that no one controls. 

Buy on CEXes if you want, send it to self custody or burner wallet immediately, say it's your own wallet (if asked), send to who ever you want and go on with your business as usual. 