Net setup - all good but high humidity

[Homebody]

I do have a space heater but I haven’t been using it. I was worried that it would make the whole set up just to warm, but I will turn it on and monitored closely and see if that helps… Does this seem like it’s the right distance - meaning how close it is to the side of the tub?

Assuming that moving the tub to a warmer room isn't an option, I would set up the heater (regulated with a thermostat) as far away as you can and move it incrementally closer until it's able to maintain the ambient in the enclosure in the 75F-80F range.