In GTA V, I am lvl 393 with over 190 million R* dollars earned, in RDR2 I am lvl 168 with about 30k of R* dollars earned.
Not going to sugar coated it, I play games online daily but I don't smoke cigarettes or snort coke or other nasty stuff so I figure its a benign addiction. The games that I continue to play are ones that change constantly and challenge me, GTA V and RDR2 are my main ones. Those games have strong elements of randomness, you never know what will happen when you go online. Some days there are a ton of asshat griefers making everyone's lives miserable, some days everything is as smooth as silk and there is a feeling of accomplishment. For the most part, I play co-op missions, those are the ones that are random, no two are the same. That is what brings me back to the game not the trinkets, baubles or trophies but not all players are the same, some players need those things.
The problem I think is that in GTA V there were a ton of missions/races/heists at the start but in RDR2 there is a limited number. GTA V benefited from a long developmental history, previous incarnations of the game provided a framework. There doesn't seem to be the same depth of game development with RDR2 and I am not sure there ever will be due to the fact that the PS5 will take up a chunk of R*'s time. It wasn't until GTA V introduced heist missions that the game really took off, RDR2 has introduced roles such as trader, collector, bounty hunter and now moonshiner in an attempt to provide interest.
What it comes down to is personality, some people work to accumulate things and are disappointed when there is nothing left to accumulate, some people work and stay in the moment and enjoy the the journey, its that simple, a new hat/clothes/gun won't solve the problem but it would be nice.