Thank you everyone for the feedback and advices. After some thought, I'll just stick with my 686, first learn how to shoot it and enjoy it before jumping for another one. In a few months/years from now, I'll be able to refine my judgment and see which one I need/want. I'm just at the beginning of my gun journey, no need to rush!
Btw, I finally had the time to finetune the sights, here's a pic of 10 shots with .38 special at 25 meters/27,3 yards (five 10, three 9, one 8, one flyer, not that bad)! First five shots two-handed, five next shots with one hand.