The main thing you're looking for is at the bottom, but you need to enable the RCS debug menu to see that.
Open Google Messages (GM) and turn off RCS chats before continuing.
In GM, Click on the magnifying/search glass at the top to perform a search
2.1 Type the following with the "*" symbol included: *xyzzy*
2.2. In a few seconds you should see "debug mode enabled" pop up on the bottom of the screen
Go back one screen and click your picture in the upper right corner
Select Debug
Select RCS
Select "Report RCS Connection State"
Etouffee provisioned: true
Even if RCS is "Connected" in green, you might not be able to still send RCS messages to other users who you know support it. For the users who've said they got this working they said Etouffee needed to provision. If that's you, i think maybe just wait. Some people have reported that Etouffee can be throttled. It should connect in time.
It seems the BugleE2eeEtouffee service doesn't really emit any logging so you won't see much in logcat.