Looks like Verizon has RCS through their own message+ app but only works between Verizon devices, which is pretty crappy. I have a Verizon S9+ and just downloaded google messages. I already use it on my personal Tmobile Note 10+ and sending messages between them is still SMS. I'm connected to the RCS network with Tmobile but I can't turn on chat features in app on my Verizon phone. Tells me the carrier doesnt support it.
On Verizon network, To get RCS features on Samsung S10 5G which I have. What I did was reset and restore my phone after the Android 10 update due to location errors from Carrier Services which is vital for RCS.
I started out brand new. Then I installed Google Messages and Carrier Services. I opened google messages and went to chat features and entered my phone number to be verified. It took awhile. I then setup the settings like I like them. The other apps like Samsung messages and Message+ don't use RCS yet. Everyone has to use Google messages in your circle to get RCS to be utilized otherwise it is basic messaging. Verizon tech coach yelled at me cause I did this. They said it would mess up my phone. Well, it hasn't yet and no errors. I don't know the problems and I believe they are pushing people to buy the Pixel to use RCS. Well go to rotate it and stick it up your canary. I got it to work and I will keep using it till I have reset my phone.
I have Verizon and have has RCS for a long time now signed up through beta and got it a few months prior. However, beta isn't necessary anymore from what I can tell just download Google Mesanger and all of the prompts should automatically appear setting RCS up for you. If your running into trouble u install through play store and then sign up for beta and reinstall it will definetly work. It's sorta pointless tho until more people get on board. Cheers and happy new year 2020