I wouldn't get too fixated on the RH right now.
Mine is going between 24% and 40% depending on the weather outside.
I know you're about to have this licked!
You got this Gramps!!
I am not sure what part of the world you are growing in Gramps, but I did a winter start this year in the North East and for most of my veg cycle, I was in the 20-30% RH range and it didn't do anything negative (might have grown faster and bigger if I had better RH) to the plants that were visible. I would definitely think I would focus on finding whatever it is that is your issue. Also, you can mist the plants a few times a day (what I did to help with RH along with hanging a wet towel and putting a bowl of water in the tent). I just don't think the RH is the cause of your issues.