Keep Lenco or get Thorens or Rega?

I have been struggling with my Lenco GL75 for a while, I can't get it to track properly with my Ortofon M2 Blue pickup, and the speed seems a tiny bit uneven as piano sounds are wobbling a little bit. There's also some distortion in the highs at some points. Walking around in the room is also making the needle skip very easily and I don't like that at all. (I can't force the two cats, girlfriend and visitors to walk on their toes like I do when I'm spinning records.) I have the original tonearm and original chassi. I have been told to try a different pickup that allows heavier weight, so I got a Denon 103R that I haven't tried yet but I'm not sure that will help my situation completely.

I love the sound from the Lenco but I'm having second thoughts, I don't want to spend more money on this turntable as it might not help. I've already spend quite a bit on new cables etc. Is it better to get a Thorens 125 mk2 with Grace G960 tonearm (1100 dollars) or even a Thorens 166 mk2 (300 dollars)? I use my old Rega P1 most of the time as it works fine even though the sound isn't as good. But I hate the weak motor, can't even clean the records properly without stopping the platter to spin. Maybe a new Rega P3 or P6 would be a good choice?

I think I need some advice! Thanks!
The achilles heel of the Lenco has always been that stock tonearm. The first thing the Lenco-modders tend to do is ditch the arm and replace it. A modded Lenco, or a well-serviced original, will have outstanding speed stability, too -- that's always been a key Lenco feature.

I'd suggest a visit to the "Lenco Heaven" website and see if the many suggestions there can help you. These turntables have an outstanding reputation, but only if you are willing to play to their strengths and overcome their weaknesses. Good luck.
Neither of those other two turntables has the potential of your Lenco. Keep it. You will be sorry, otherwise. Like Dave said, get rid of the stock tonearm, and that's half the battle. Here is a link to what might be a good candidate to replace the tonearm, for very reasonable bucks:

Or there are any number of fine vintage tonearms that can be had for similar expense, e.g., Victor, Sony.
Agree with the above. A Lenco is not a plug and play rig. The kudos offered by hundreds of Lenco-philes all assume some mods and upgrades... quite a bit, usually.

If DIYing and modding isn't your thing, a Lenco might not be the best rig for you. OTOH, you'll have to spend a lot more than a Thorens or Rega P3 (or even P6) to better a properly sorted GL75. If you're willing to get into the nuts and bolts you could put most of your money into a better tonearm. That would be the most economical upgrade path.

It's easy to get the engine and iddler wheel working well. You must register to lencoheaven to have access to the pictures describing how to check the engine...
Next step is a dedicated plinth .
If willing to work with it, the Lenco will sound better than the other 2 rather easily. You will have to take it apart and remount it in a new plinth after cleaning. A new tonearm is a must for getting the best out of it, but a Jelco 250 can do that and they are relatively cheap.
You may also consider a wall shelf for your Lenco.