Actually I got two of them.
I admit, I made some mistakes.
1) I used and relied on a moisture meter. I think I let it get too dry, or there was a lack of humidity when the AC was running a lot, because the new leaves developed crispy brownish ends and wrinkly leaves.
2) I added a pebble tray (which I guess doesn't help much) and watered too deep for the soil it was currently in. Don't know if the water evaporating kept the soil too moist or the soil itself was too compact, but it stayed too moist and some base leaves turned yellow.
So I went from one end of the spectrum to the other. One was more dried out than the other, now the better one had more yellow leaves from being kept too moist.
So two nights ago, I decided to take the plant out of the pot. On one, there were a lot of roots at the top of the pot and I was wondering if that's why certain parts of the plant were drying out despite being watered.
This one
So for that one, I gently smoothed all the roots facing downward and re-potted it in bark/worm castings/perlite/cactus and a bit of potting soil. Both plants now have nice and airy soil with roots facing downward.
This is the one that showed more yellow leaves and dropped a few when I repotted. Definitely waterlogged as it was quite compact around the root ball.
I did give it an initial drink of rainwater (let it drain right through and hope that wasn't a mistake). Then I placed the pots in front of a fan for the night, the next day was windy so I had the windows open.
I guess I'm just documenting what happens, feel free to comment if I'm doing anything wrong.
I plan to just leave it be now, dry out pretty good and be careful how much water I give it from now on, idk. I'm sure the new substrate will help, but I know the plant will have to adjust to it. I don't expect them to do much for a little bit, I just hope they don't die.
Also when I checked the humidity, it was over 50%, so I don't think that's an issue at the moment. I also got rid of the pebble tray to give them a chance to recover hopefully.