There is currently a bug that makes it so lobbies disappear from the custom games list after about 10-20 minutes and then no one else can see the lobby anymore.
The lobby will re-appear if someone leaves the lobby but only for about 10-30 seconds.
Please look into this bug as it is making very hard to get slow filling maps full.
With WC3 Reforged coming to Gamepass in ~10 days, I really hope Blizzard puts some effort into trying to fix this. It seems like a missed opportunity for such a large influx of potential new players to be met with bugged custom game lobbies, which helped popularize massive modern genres like MOBAs. Bumping this thread to try and draw more attention to the issue.