As @admon mentioned, DDNS can solve the issue of the IP address changing. This would apply to any ISP that does not use CGNAT.
Before switching to AT&T fiber you should verify that they don’t use CGNAT. If they offer static IP’s that’s a bonus. One last thing while we’re talking AT&T fiber. I’ve read over at r/ATTFiber that the pass through method they use is not 100% pure pass through. I’m not sure if this would present any issues but read up on that as well.