Some people have said to me, the “best” bassist is the kind you will only miss when they stop playing. That’s in a band setting.
Also in a band setting, I’ve had a songwriter base songs from stuff I’ve been doing - to add tension in a song I’d do a little run of notes and he’d get the rest of the band to follow it. I can send you a link to that song if that helps? He also walked in on me doing volume swells with harmonics one day, and wrote an entire song around it. He said I was “the best bassist” - for him. I’d equate that version of “best” to the likes of McCartney - an integral part of the band’s “sound”.
And then there’s “best” with the idea that music is a sport, and you’re all technique and party tricks. That to me is fun but ultimately futile because there’s always a bit flashier, faster or more technically gifted - and The musicality takes a walk the flashier you get.
But I’ve done that route too - and just allows you to develop tools for the second type of “best” bass player.
The reality is, the “best” bass players are the ones who are paying their mortgages by playing bass and not stuck for a job.
The rest of us humble mortals got day jobs and are now too entrenched in “real life” to make the jump into a job as a professional musician.
I sold a bass to a guy once who was a “pro” and reeled off an impressive CV, but when he played the bass to check it over...I couldn’t believe how sloppy and amateur it all sounded. But fair play to the guy - he was a busy man...
Whatever “best” is, it’s whatever makes you happy and sits well in the music you’re involved in.