That's the way I've been with this Sadowsky UV40 I got a couple of years back. Strings buzzed no matter what I adjusted, tried several brands of strings including flats, nothing worked. Action too high, decided to have my local repair guy shim the neck, that didn't do it. Very frustrating after all I'd heard from players that owned one, bass just sat in the case for months. Was thinking about putting it on ebay this week but decided to give a last ditch attempt to make it play like I wanted.
It has Prosteels 105-45 on it which it seems to like so I went back to bass 101. Removed the shim, reattached the neck and started working on lowering the saddles to a normal height. I got the action a lot lower but still had the fret buzz. After adjusting the truss rod along with the saddles I was finally able to minimize the fret buzz so it was at least playable. Been tweaking it very slightly every couple of days to further minimize the fret buzz and I'm proud to say I have low action and an almost buzz-free neck. I would have regretted selling it for sure.
G-string is maybe a teensy bit higher than I want but still comfortable. Fun to play now and I will be keeping it. Loving that Sadowsky preamp and sorry I missed time playing it.
My old '91 Les Paul bass was like this, just never felt quite right after my efforts or a shop's efforts so I never played it. Then one day all the planets aligned and I found the magic setup formula and that bass was a monster after that.
I will admit my setup skills are average at best. Ever had a bass that frustrated you to the point of selling it?