Your humidity is too high at 70%.
Those low leaves going spotty may be nothing to worry about, since it's only a couple leaves, and low leaves get ugly over time- it's normal.
I can't see thrips or their damage in those pics but look closely for silvery trails where they chewed the leaves, and poops, and little larvae about 1-2mm long and tan colored.
The pale plant in one of those pics needs a pH runoff test done on it pronto. You may also be over watering.

Edit: Zooming in, I see potassium deficiency or lockout in the pic where you are holding the leaf. Test your runoff pH of all plants showing rust colored spots. Usually that is associated with wet, acid soil.