Without Spoiling Too Much - How Do I Set Myself Up For Success Long Term?

Doing my first play through on PS5 and focusing on getting as much money as possible with Arthur. However I have seen that eventually I will switch to John. I fear that all my work will be for nothing if I build up Arthur just to no longer use him. Is there any tips on what I should be doing to keep my money for the long haul after switching characters? I don’t want to give it all to camp. Maybe the bank if possible?