Even some of the people who think OSRS may be more "popular" than RS3, they still pick RS3 over OSRS.... like this one:
1 RuneScape
"Despite being less popular than its Old School counterpart, RuneScape is a regularly updated MMO that offers plenty of content for you to sink your time into. In recent years, it's pivoted to more active gameplay, cutting down on the grind that has characterized RuneScape for so long. It's a nice balance between grind and action, but overall it's one of the most casual games on this list.
RuneScape has undergone massive changes over its life, which is good or bad, depending on where you stand. However, if you're looking for a casual MMO that is forgiving to new players, you can't do much better than RuneScape."
3 Old School RuneScape
"While Old School RuneScape's gameplay is addicting, it is a little dated as it's based on the 2007 version of RuneScape. Try RuneScape if you want a similar but modern experience. Both games are cross-platform, so you can pick up on PC where you left off on mobile
https://www.androidpolice.com/best-mmorpgs-for-android/
Try RS3 if you want a similar but modern 2023 experience
. Get it?