You can’t control the use of the machines. Every one of them will have too much detergent and softener used previously.
The best thing to do is use a machine that gets a lot of use. Pick one that has just run a bunch of loads. That way others will have flushed out the machine before you use it. Don’t go too early in the day since the nasties can grow overnight.
Soaking in TechnoFresh will remove all odor from the machine if necessary. You can use half a capful of TechnoFresh in each wash to kill the odors. But that can get expensive. Maximize the load size to be most economical.
Use almost no detergent and softener yourself.
Let me know how It works out.