Broad mites are one of the hardest pests to deal with because of a few reasons:
They are very small, only visible with 100x magnification and the damage they do to plants are very much like nutrient or ph issues. That's why most growers who are not familiar with these pests mistake them for something else until it's to late. (It might take a few grows before you find out the source of your problem)
Besides that they can become resistant to chemical pesticides. (Most natural remedies don't work anyway.)
These are nothing like spider mites which are easier to get rid off. Neem oil which is a very popular natural bug spray will do nothing against broad mites.
What seems to be working quite well is Diatomaceous Earth (https://amzn.to/2U2ZpQe). This is a very fine powder that is not harmful to humans (get food grade diatomaceous earth not pool grade) but will kill mites. The powder is like glass to them so when they crawl over their exoskeleton get's damaged which causes them to dry out and suffocate.
Since diatomaceous earth has a mechanical working and not chemical it's very safe to use on plants. You just have to be careful not to breath the powder in. That's why wet application is easier then a dry application. The powder spreads better over the plants and you can't breath it in when applying wet.
Make sure you spray most powder where the mites like to hang out that's on the underside of leaves and new growth. (A sprayer like this works well for this job: https://amzn.to/39Nbhws) And make sure you are applying it on the base of the stem so mites can't crawl back up on the plants.
You can apply this also on flowering plants since it's not chemical but you don't want the powder on your end product so a good solution might be to water cure your buds when harvesting.
If the powder washes of from rain or wind then reapply, because of this "DE earth" is easier to use indoor then outdoor where you have all the nature elements.
After all the broad mites seem to be gone, don't stop treatment immediately since the eggs can lay dormant for months.
This product also works on cyclamen mites and russett mites with the same effect. As well a bunch of other pests that have an exoskeleton like: aphids, whiteflies, thrips, spider mites, ...
IMO DE earth is very underrated because the mites don't become resistant to it, it does work unlike most products and you don't have to reapply it "constantly". Besides that it's cheap and not harmful to humans and plants.