Back in the old days I had a ping-pong table that folded up. It worked fine for many different types of games. The pool table worked pretty well too, but what I really like and still use is the 30” by 6’ folding table. The table cost me $47 at Office Max or some office supply store like that. I leave mine out all the time so I have a place to do my bills and sort clothes from the dryer. Kids like to do art there too.
When we play I toss the blanket from when I was in the Air Force over it and clamp it down around the edges. It works for fantasy game when we go tactical and games like A&AM and Flames of War, as well as most Sci-fi games. And if you play cards it works very well. Not having hexes of 1” grids has never been a problem as I have a small stash of six-foot mini tape measures from Home Depot I bought for a buck each.
And way back in the old days my cousin had a train layout we played on. Whatever works is fine.
As far as the paint over the particleboard, I must say it didn’t work so well. After I painted it the strand lifted a bit, so I sanded it down and repainted it. Well, it lifted again but not so much, so I re-sanded it. The third coat and it is still a pretty rough surface, not what I expect you will find easy to write on with the dry erase markers. I ended up making another one and hinging them together and screwing them to the sand box to keep the neighbors cats out. Worked better at that then as a table for Star Fleet Battles.