This excellent advice! In fact it should be pinned somewhere useful on here. Really well explained Paolo 👏
I try to do the same kind of thing. When I started learning upright, I gleaned what you just explained from DB tutorial videos. These nuggets of wisdom have also transformed my BG playing completely, especially the using of the arms weight to apply the (not really that much) pressure to fret. That's a whole massive levers-worth of free energy to utilise. Now my thumb is just a gliding guide rather than the one half of cramp inducing G clamp that it used to be.
Regarding using OFPF... I was taught this way and stuck at it for years, eventually getting horrible clicking in my wrist when fretting down the low end. Simandl saved the day for me.
Hey, it also worked for James Jamerson, who was originally an upright player! 😉