Doesn't matter what you do the pot soil composition. If the problem exists in the environment.
I see a 11L fabric pot that is oversaturated, soil compression most likely too high for roots to penetrate.
65% rh daytime as a new grower is akin to suicide without and understanding SPAC and how water moves from atmosphere to atmosphere. You need to incorporate some form of evaporation to assist with the roots transpiration otherwise you are throwing water into a pot with no way of moving the water.
Roots can only pull water where they can grow. If soil compaction goes above a point the water gets trapped and it's just a matter of time.
Fabric pots not as airy as one may be led to believe make sure there is air hitting the pot. Make sure there is a dry period in your day/night cycle. Water doesn't move efficiently nothing works.
Understand this.
Oxygen moves about 10,000 slower in soil than air. Oxygen moves 320,000 times slower in saturated soil.
Soon as you water. You want it to reach a point of "optimal" fairly quickly and get that oxyben moving 10,000 times slower ASAP.
As soon as you water, new oxygen does come with the water but if the soil stays "above a certain moisture" then Oxygen will stay at 320,000 times slower. Oxygen is quickly used by the plant and micros but everything moves so slow its almost like a oxygen lockout. No matter how much perlite you got.
As soon as Oxygen becomes low, you normally ally get 30-40 atp per glucose molecule in oxygen rich conditions. To about 2 at per glucose in low oxygen conditions and as a by product acids are released that will acidity your grow and skewed pH.
Need to warm things up and get the water moving. Water is the universal delivery solvent used for cooling and nutrient transport. Like an elevator on a construction site, you want it running faster rather than slower.
Gluck.