Heating bread in the microwave oven and wetting
There are two main strategies I employ to combat sweating in the microwave.

Microwave the item in short intervals, rotating in between each round. This will help steam dissipate rather than collect on the glass. Using a lower power might also help the item heat more evenly and lose less water.

Place a paper towel or tea towel under the item. This will collect the moisture so it doesn't pool and make things soggy.