I searched everywhere on the Samsung apps to see about RCS but I also did a search in general settings for RCS but nothing came up. I can't imagine I'm the only person with an S10 that uses the Samsung text app. It's unfortunate that Samsung hasn't added thatGive it a bit. Pretty sure if you have the latest build its server side. Also you have to enable RCS in settings.
Also give it a shot as default, what do you have to lose. You can always go back.