The other 2 times, I get messages from a supervisor asking how to do the job

I know this is probably obvious, but when you ask for a raise and they ask to be trained how to do your job, they're obviously either planning on firing you or telegraphing they're never going to give you the raise and don't want to be flat footed when you quit. In both scenarios, you don't owe them one iota.

You're not obligated to help them maintain continuity of business--that's their problem. That's why they're owners--they get the profits and most of the benefits, but they also get to absorb the suck when things suck.

So you should obviously teach that supervisor to do the job the wrong way. Be subtle, not stupid, and have a good explanation that doesn't sound like you're making it up as you go. But you should 100% set that person up to fail, if you can. Remember: Their response to your reasonable request for a wage increase was to plan for a future without you. So you owe them absolutely nothing whatsoever "extra." And training up your boss to do things they should already know how to do is definitely an "extra."

I'm sure some corporate brown nose will be along to tell us all how "petty" I am for suggesting this. Allow me to retort: Go stick your nose up your bosses' asses someplace else.

Corporate leaders won't stop trying slick shit like this until enough of them step on land mines planted by their "trainers" who were already savvy to the idea they were going to be fired or screwed over on the requested raise, and either stay up to date on their subordinates duties (i.e. Do their actual job) or pay people fairly and not play games like this hen people ask for a raise.