If IPv4 ban, it is indeed 100% ineffective. Nearly all ISPs either CGNAT or rotate addresses. If IPv6, the ISP just forwards a 64 bit block and leaves it at that. You must call and request a new IP block. In which case you'll be told yes or no. If yes, it's either free or paid.
I know with ATT Fiber, they don't offer address changes unless there is some security or service interruption reason. You have to unplug the modem for 30+ days so the lease expires if you don't want to do rounds with support. My IPv4 address has changed once, but my IPv6 address block has never changed.