How good does a TT have to be for a good cartridge

I actually think it's the other way around. With a cartridge that is just "good", low- to middle-priced, plus a really good tonearm well matched to the cartridge and and an excellent tt, you can get better results than using a very expensive cartridge with mediocre tonearm/tt. So, first get the best tt and tonearm you can afford. Then play with cartridges to your heart's delight (and your ears too).

I hope I accurately figured out what you wanted to know and responded to it.

A better table will improve the sound of a modest cartridge more than a poor turntable will be upgraded by an expensive cartridge.

As long as the arm is compatible with the arm and you have a good phono stage you will get better quality sound from a better cartridge on your tables. Though there are better turntables out there your tables are still very good and should work well with better cartridges

Although I may be lacking in experience, compared to many on this site, I used for several years a Dynavector XX2MKII on a Scout Signature, with a couple of phono stages, Simaudio Moon LP 5.3 w/outboard power supply, then a Modwright SWP 9.0 SE. What happened is the Scout just sounded much better than the Lyra Dorian it replaced.

I'm off in a different direction now, I'm in the finishing stages of a Garrard 401 restoration/upgrade, mounting a Dynavector 501 arm, and I'll use the XX2MKII here as well. I'll see if this project sounds better, or just different, but who knows?

I'd sure like to try the Dyna XV-1S, or an Ortofon A 90, but those are not in my comfort zone money-wise.

The lipstick adorned pig enters in here, too, but I couldn't tell you where that is.

Good luck, and good listening,
Dan