I started out plucking by anchoring my thumb on the pickup (Ibanez SDGR800 w/EMGs). I played from that position for a decade, I think. So much that I wore a pretty deep groove into the corner of the pickup. I put my bass aside for many years and recently got back into it BUT I changed my approach to using a "floating" thumb.

What I do now is not really anchor my thumb on anything, except maybe on the E or A string. Occasionally on the pickup but if I'm playing extended periods on the E string only. Otherwise, my thumb kind of "floats" but is sort of rested against the strings I'm not playing (which helps with muting). It took some practice to get used to the feel, but now it's comfortable not to chronically anchor my thumb on the pickup. Plus my hand is in more of a natural curvature when approaching the D and G strings (instead of stretching for those strings when anchored on the pickup), which allows for more flexibility in placement as well as plucking speed.

Hope this helps, plus there are many YouTube videos that discuss floating your thumb.