How to access Expert settings on Home Internet

FYI I discussed this with Tmobile tech support and they said that Expert settings are not yet available on the 5g modems but that they have a major upgrade planned soon (no dates or timeline given).  So the settings are very basic right now on the 5g modem but there should be feature parity with the 4g modems at some point.  For right now, I've simply plugged in my wireless router (still in router settings) to the 5g modem and everything is working fine.  I have lost my ability to manage port forwarding but I can manage until they fix this capability.  I have not encountered any double NAT issues on the network yet (other than losing port forwarding).  There are capabilities I will lose if I put my wireless router into bridge mode so for now I am leaving it in router mode unless I encounter networking issues.