Condensation on HVAC, mold on joists/subfloor in basement

I have heavy condensation on the plenum and supply line near an exterior wall/window in my unfinished basement. I have mold and moisture on my subfloor and joists just in this 3 sections. I sealed up all of the major HVAC leaks there with mastic and HVAC tape, trying to dry out the subfloor before treating it for mold.

The humidity by that window is 70%, by the next window over it is 52%. I can’t feel any warm air coming in around it? This section is a cantilever for our master.

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