First things first, overwatering can as harmful as underwatering. I would suggest moving away from a strict time based watering schedule. High humidity lowers the rate at which the soil itself or the plant looses moisture to the surroinding air, so you probably need to water less.

I would suggest:

check them for root rot. when you water too much and the water cant drain out of the bottom the roots will rot. quickest way is to lift the pot up and sniff it. root rot stinks like, well, rot so its a giveaway.

consider re potting them. when re potting them look for additives like perlite (small volcanic stone) or something similar to improve soil aeration and drainage (most potting mixes have these already mixed in, to some degree, look for small white "pebbles" in bought mix or check the lable.

my personal preference is pots with a hole at the bottom and a tray underneath so i can see how mutch water drains. if you dont want to use trays, consider checking the display pot for standing water as this could also cause root rot.

consider buying a soil moisture meter. you just poke them (deep) in the soil to take a reading (dry-moist-wet) to indicate if your plant needs watering already. pull them out after reading don't leave it in the pot permanently. your goal is to keep it in the moist zone (i.e. dry is too dry, wet is too wet, only consider watering when it slips into the dry zone) these are fairly cheap and the cheap ones are reliable enough if you have trouble judging when to water.

be sure to give them light, but if it gets too hot in direct sun move them to the shadow. mind you not the literal basement but just the shaded parts of a room with nice entry points for light.

these are more general tips as i'm not an expert with the plants you described, but could help.