Whew! I thought it was just me! I'll be going to war with some of these ideas tomorrow!
Good luck.
It took us a while to discover whether we had fruit flies or drain flies - we also have a drain problem, and spent a lot of money on gel stuff that you put down the drain. But it looks now like they were definitely fruit flies.
They haven’t bothered me much, but they drive my husband nuts. I think we’ve finally solved it.