40-50% RH is fine during the day.
18 x 18 x 24 (4.4 cu. ft.) is way too small for an adult—just over 1/4 of what it should be. At one year, he should be in a minimum of 24 x 24 x 48 (16 cu. ft.), and preferably larger.
https://chameleonacademy.com/veiled-chameleon-care/
By 'humidifier' do...
Welcome to the forum.
How cold, and could we see more pics of the enclosure from top (showing lighting) to bottom (showing substrate & drainage).
Is the enclosure all-screen or hybrid? Hybrids are much easier to control temps & RH, but if you have all-screen there are ways to improve...
As long as you don't look at it too closely. 😁
At least it's functional.
The blocks in the link at the bottom can be done with a hand saw, and built up for more height if needed.
We could probably come up with other solutions with more information (pics of enclosure, bulb strength, actual...
Pothos always grow like weeds. So do some philodendrons & inchplants.
IME, they're kind of like earthworms; cut them in half and both halves will grow into new plants.
I have all three. For the first 10-12 feet, I tried training them around various branches,supports, and other plants...
Why? Maybe near the top, if they're becoming a fire hazard or showing signs of stress.
I'd look up each species for the right way to do it. Some (e.g. dracaenas) are better pruned at specific times during the year.
He looks OK to me. If he's self-regulating, IMO that's a good thing.
Mine does the same thing. He didn't eat for 2-3 days in a row, then today he ate 6 mealworms and a roach. Some says he'll eat 2 crickets; other days he'll eat 5 or 6.
Welcome to the forum. I only wish it were under better circumstances.
There's no harm in waiting until you're sure—or ready—a couple/few hours either way.
How handy are you? I built a rig for my Missus' tortoise table that could easily be adapted for atop a chameleon enclosure. The UVB is mounted on the underside of the flat 1x8, which leaves enough room to put a clamp light on each side without interference. Could be modified to go higher if...