Yes, both Google and Samsung Messages. Did you install carrier services?
Having said that the only RCS service I've confirmed is the delivery receipt, I have not seen typing ot read receipts.
Galaxy S21 Ultra 512g(VZW), Galaxy Book (original, VZW), Tab S8 Ultra, Tab S4, Galaxy Watch3(VZW), M8 Smart Monitor
Do you have an unlocked S21 Ultra or did you buy it through Verizon? A lot of people have issues with their unlocked S21's getting chat features to work. From what I know it's the carrier's fault because they want you to buy the phones through them. I have the unlocked S21 Ultra and I'm on AT&T. At first it didn't work, so I went ahead and flashed the AT&T firmware on my phone, now when I restart my phone I get the AT&T logo at the bootup. RCS on Google messages still didn't work for about a week, kept getting the same thing as you, trying to verify number. Now about a week later, it suddenly worked and I'm connected on Google messages and I can see read receipts, typing etc.
Ah ok, not sure then. Like Bill-e said, do you have carrier services installed from the play store? Also doesn't Verizon have their own messaging app that works with RCS?
Sorry to hear that, I'm not sure then. Only thing I could think of is to flash another firmware to your phone, but that's not a beginner thing to do cause you could brick your phone if you're doing it wrong.