gullikit hall effect sticks reportedly have a square outer limit, which leads to overshooting/disproportional diagonals.
elecgear tmr sticks supposedly do have a proper circle pattern.

I can tell you a set to avoid, the AKNES GuliKit sticks (sold on Amazon). For some reason, when you go to calibrate the sticks, the area the sticks can move show up as squares instead of circles. This means when a stick moves at an angle (top left, bottom right, etc), the stick moves into one of the corners of the square. Since there's a longer simulated distance for the same hardware distance, moving a sick at an angle registers faster than moving a stick in a cardinal direction. It's weird. It was too much of a pain to uninstall, find new ones, then reinstall, so I've just put up with it.

I got a set of gullikits which I believe work both in the oled and lcd deck, you have a switch for which version you're using. They are great and have never let me down. My case was the same as yours, my left stick had a drift.

Some say the gullikits have a square box and that impacts how it responds, but I haven't noticed it. Then again, my deck is for couch gaming mostly

Edit: see comment below, the gullikits are not interchangeable

I have the handheld DIY hall effect sticks and have been happy with them.

A lot of stick drift is actually caused by debris or sticky residue in the thumbstick housing, I've fixed stick drift on a lot my personal controllers just by spraying some plastic-safe electric cleaner spray in around the drifting stick.

That said, I did replace the sticks on my OLED deck because the capacitive pad came off. I used a set of Gulikit Hall Effect sticks, and they've worked pretty well.

I have heard that some of their older stick designs had issues like square dead zones, not sure if that's still an issue. I know they improved their LCD stick designs so that you no longer have to solder anything or buy different products depending on if you have type A or type B sticks.

Been using the Gulikit sticks for three years. No complaints.

I have the old gulikit ones and don't really think about them ever which is good. I never tested/confirmed the reported issues on mine or accidentally triggered them but it would be worth finding the video explaining it before committing. You don't have to do a full teardown but its involved enough that I wouldn't want to do it multiple times... I say as I look at the ram and wifi upgrades and the sparkly button replacements sitting on the shelf.

Actually I also have a full shell swap and the aftermarket oled in the cabinet too...