Temp is directly linked to how much moisture the air can hold. Lowering temp without raising rh you will need to setup a negative pressure within the tent extracting to a desired rh. Air going in will need to be cooled to consistent level or have a ambient direct line to the cold temps and outside air.
Plants need fresh supply of oxygen at night and co2 during daylight if your not measuring or have a replenishing source both can quickly be gobbled up in a "sealed room"
If you breach the compensation point of co2, growth will be effected dramatically.
Have rh set to extraction thresholds. Ambient line to outside with 3,4,5,6 180 bends depe dong on needs, each bend will double the amount of force required to make air go around that corner. Basics.
When a tent extractor comes on to set the rh to 50, then 80%90 of the air drawn into the tent comes from lower intake of whatever room the tent sits in, while the open air ambient line brings in 5, 10, 15% depending on # of bends ,fresh air packed with oxygen and co2 as a bonus.
Careful placement of ducting inside the tent will prevent heat escaping or humidity.
Only other thing you can do is use a portable ac.
Good luck.