Swap memory, a good or bad thing?

Swap memory is not detrimental. It may mean a bit slower performance with Safari. As long as the memory graph stays in the green there's nothing to worry about.

You want to strive for zero swap if possible for optimal system performance but it's not detrimental to your M1.

as long as you get the RAM from a trusted retailer, then adding RAM is definitely beneficial. i would recommend shopping at OWC to find your RAM. there's also instructional videos on their site to help you determine if you can do the install for your self or farm it out.

oh, ok. i thought you were asking about swapping the RAM on a mac where that's possible. if i had known yours was an M1, i would have known better than suggest something that's not possible. :)

RAM is your fastest memory. Swap is slower so you want to minimize the use of swap memory. I minimize swap usage by not having many apps open simultaneously. Using swap will not damage your computer.