You just need to learn how to do whole plant water dips. It's easy, you can even dip a 5' tall plant with two people and a trough of water.
Problem with all kinds of chemicals against spider mites is they eat chemicals for breakfast. They're not insects. IIRC, no insect can feed on more than about 50+ crops, but some species of spider mite prey on more than 100 different crops. They evolve immunity fast, so we always rotate chemicals.
Things like water, diatomaceous earth and vacuum cleaners are mechanical methods that mites have a harder time evolving around, so they're more effective.
Unfortunately, the water won't really eliminate them either because eggs. If you hit them every 3 days, you interrupt their breeding cycle and that may not eliminate them, but will knock them silly. Double dips will get the eggs but take at least twice the time. First let them stand a while (in the dark) with a strong soap or neem solution, then rinse with water.
Friction is important with dipping, so a lot of swishing or lifting the plant in and out of the water does a better job than just soaking.
Also, people worry about the water washing, or knocking the trichomes off. I've found that, either it doesn't really happen, or maybe the trichomes reform after dipping. Either way, it doesn't seem to do anything bad to the potency.
I've gone into some big commercial grows where the boss was ready to throw the whole web covered crop away, water dipped all the plants and they're ready to harvest the next day. From bust to boom in one simple move.
"My dream is a five pounder at the end of every cul de sac in the land!" Mr. Greengenes