I broke my ring finger earlier in life (on what would become my fretting hand) and did not get it reset properly, so now when I bend my fingers my ring and pinky fingertips close to the same place…this makes using both separately for fretting impossible, so I only ever use the first three fingers…
it takes some adjustment to instructions given in bass buzz lessons etc. and more micro shifting but I don’t think it is a big deal compared with what some other people deal with
I am also lefty and would never switch to righty as the plucking hand is where the rhythm lives so I want that to be my dominant hand
here is me playing a cover I just posted where you can see my three finger fretting (with poor old pinky just along for the ride)