It depends...
5G-Fixed Wireless Access, at least here in the US, is IPv6 first (and native) - so IPv4 is handled as a legacy stack with mechanisms like 464XLAT (similar to, but not the same as CGNAT).
Practical experience with 5G-FWA - TMobile's IPv6 is ok, one thing to note is that they don't provide a PD, which makes internal addressing rather interesting (not in a good way) - I know this first hand as I have T-Mobile 5G Home Internet. Also they provide an RFC1918 IPv4 address, in my case it's 192.168.12.0/24 on the "WAN" side, which means any kind of port forwarding in IPv4 is basically not possible.
TMobile is one of my ISP's, the other is CoxHSI - and there, they're fullly dual-stacked with public IPv4 and IPv6 addresses, and they will typically issue a PD with a /64 - less than optimal compared to a /48, but this is a consumer account.
I usually encourage folks to give it a try with enabling IPv6, but at the same time, I'm also aware that many Router/AP's may have issues with IPv6...