Yes, search up the various other bigger drawer boxes, watch boxes, earrings boxes, accessories boxes, et cetera that some other people use for their IEMs. There's pictures here on /r/headphones, and also Head-Fi, etc.

There's also some good earbud cases from AliExpress for like $5-10, lol. But there's always the $5-10 cases from Amazon too. Those will work just fine for individual IEMs/TWS earbuds/etc.

For humidity, maybe get those tiny Ziploc/plastic bags and put them in there, maybe don't worry about static/etc. Don't worry too much about humidity, just put your electronics away from the window during winter if you don't have HVAC or constant heating.

How to maybe soundproof your room for better noise reduction/isolation: https://www.reddit.com/r/headphones/comments/10epr17/struggling_to_enjoy_my_headphones_in_noisy/j4t4qaw/

If you get (legit, the expensive heavy ones, not the light/cheap/etc. ones) blackout curtains and tape them, it should do some changes. Though actually even using those plastic film thermal insulation kits did nicely as the vacuum seal on the window reduced the sound a lot.

Those thermal insulation kits will help a lot with not needing to run the air conditioner (or heater) all the time, you can keep it on a timer if your AC unit has that option. Just make sure to achieve that good/perfect vacuum seal with the windows when it comes to taping it. There's also those door draft stopper or like foam you put at the bottom of the door, those can actually help quite a bit too with retaining the heat/cold, believe it or not.