Now, I don't know how to insulate the roof to avoid condensation and moisture issues.

Some of the failure mechanisms are rusted connection hardware, crack treads, spalling from freeze-thaw cycle, and decay from moisture.  

If you are waiving, you need to determine the source of the water moisture causing the mold and the extent of the mold. sometimes, mold can grow in non-visible areas and can be worse than visual assessment. 

It's all particleboard but what they use tends to be thicker than Lowe's, reinforced better at the edges and the countertops have a better laminate round-over wrap to keep the moisture off the particleboard on the edges.

The most common reason here in elderly homes is an uneven loss of moisture content in the joists.

I got a hold of the Seller’s disclosure and learned that the property had some stucco repairs done: On 6/25/2021, the Stucco Company did a Moisture Inspection Summary that reported back high levels of moisture in the walls, aged sealants, sealant separation, missing flashings, It was highly revommended that “a follow up inspection be done within 12-24 months after all repairs are compelted to ensure that the moisture levels remain within an acceptable level.

Personally, at first glance, I would not take on this project because the exterior, alone, looks like a nightmare of work and cash output and I can't see the condition of the eves, other wood trim, roof nor whether there is a basement that has moisture or water from the melting snow and maybe the basement alone needs serious work and cash to make the house is a condition where someone will purchase it from you.

There are high levels of moisture near all windows and both back doors (maxed out the inspector's meter).3.

Recently purchased a SFR but now I'm seeing some moisture issues around some windows.

If there is a dirt floor in the basement, be aware that the excess moisture can rot out the floor from the underside and can be more prone to pest infestation from burrowing.