I'm using an EE unlimited data SIM in a 5G router and it works great.
I realise it's location dependent, but so far so good, no downtime in more than 6 months and avg speeds of 300/80 Mbps.
Haven't had any problems with CGNAT for regular usage, browsing, videoconferencing, remote work etc. I did have to disable IPv6 in the APN as it was causing issues.
Time With Provider: 6 Months
Package Name: Unlimited data, pay monthly sim