I'm going to suggest a review of your priorities.
As between turntables, tonearms and cartridges, most owners and manufacturers of high end systems agree that the priority when funds are limited should be table first, tonearm second, cartridge very much third (fourth, if one includes the phono stage).
My own experience with multiple setups confirms this. An expensive cartridge on a cheaper table or arm often sounds like dreck. OTOH, a capable table and arm will help many inexpensive cartridges play and sing well above their price point. I own a $200 MM that outplays any $1,000 MC and most $2,000 MCs... but only if it's mounted on my main rig ($6K table, $5K arm). On my cheap ($1K) rig it sounds totally blah. IMO, this is why you haven't fully enjoyed those MMs you've tried. You've never heard what they can do on a really good rig. I guarantee that if you heard them on a rig like Jim Perry's, mine or some other's here, they'd shatter your preconceptions.
Test every recommendation you receive against these priorities. For example, Jim Perry's recommmendations (while not "new" equipment) meet these priorities perfectly. His suggestions were sound and I agree with them wholeheartedly (with a personal preference for the Basis).
Additionally, with a really good table and arm, you could easily buy half a dozen MMs and swap between them.
Note: I am not dissing MCs. I own a couple, including an $8K LOMC that's easily the best cartridge I've heard. But if I put that cartridge on my cheap rig, it reveals all the weaknesses and the combination sounds like crap. To play up to their potential, highly revealing and dynamic MCs require highly capable tables, tonearms and phono stages. Your stated budget won't accommodate all that. Buy a good table and arm now and enjoy them for many years. Cartridges can come and go.
Happy hunting!
