I think Jagex also has a limit to the amount of accounts that can be made per day. Residential IPs would be helpful for this. I’ve read that Datacenter IPs will ban tut island accounts very quickly.
im quite sure theres a bot somewhere on tribot where you can give it a notepad file and it will mass-create them. but you will need some proxys otherwise all will probably just get banned after tut island as mentioned above.
you could create or buy a script that does it with cli and auto populates into databases/excel info with muling/creating new ones on banned account