Here is Rockstars ToDo list for Red Dead Online:
1) Ban people for having too many Gold Bars
2) do nothing
3) do nothing
4) do nothing
5) do nothing

Indeed. I'm shocked we don't have a way to select the difficulty level for many mission types, and it sucks you're stuck playing on the highest difficulty sometimes. :/

It's terrible game design. o_O

Sadly, I wouldn't expect an update to address this - Rockstar has abandoned this game. :(