Do you have an old phone? You could make an alternate account just to kick yourself out.

I finally did that last week. It seems like everyone except one player around where I live is Mystic, and the one Valor player doesn't play much. So all gyms are basically blue for 20+ days, until Valor Man decides to take a walk and take over all gyms in a row. So 12 pokemon kicked out, but only 50 coins collected.

So I took my old, slow as hell, phone and created an Instinct account. Just to kick myself out of the gym closest to my flat. I leave a weak pokemon in there, and I'm just happy about any amount of coins it gets before another Mystic kicks it out. Then I go and put another of my main pokemon in it. The next day, rinse and repeat. Often I end up helping (hopefully) five other Mystic trainers every day, so I like to think I'm doing something good.