To do things correctly, you'll need to activate another BYOP TF/Verion SIM WITH A TRANSFER from the current SIM/phone number of the G5 Plus, and provide the IMEI of the X4 to pair with it. If you still have that SIM, it's best to use it when you want to transfer service from your BYOP AT&T SIM to TF/Verion. * As it is now, the SE 2020 won't be unlocked by TF until it has been activated on (TF) Verizon and used for 60 days.
Using it with a BYOP AT&T SIM like you're now doesn't count toward unlocking. All is good, just surprised when the phone said it needed to install a new verion of Google Play, went through the process, but the version still shows as the same. I now have only 3 phones, all on TF/Verion: my phone is BYOP S22 with BYOP TF/Verizon SIM, my wife's phone is a TF-branded A50 with its original SIM, a backup phone is a TF-branded Moto G Stylus with its original SIM. All have lots of units and 5 yrs of service or more.
Verion Contact, Putting a SIM from a TF-branded phone into another phone is asking for ...