I've used only the Mityvac a couple of times and it just doesn't work well on the rear calipers. I let the pump do the work this time and it was a huge improvement. You don't need to push hard/far on the brake pedal. When you turn the key the pump builds pressure and stops. Then push down and you will hear the pump start. Hold for 7-8 seconds then release brake pedal (if there's a warning beep let go). Pump will run until pressure is up again then it will stop. Check the reservoir and the drain bottle.

On the fronts I found the beeswax (cheap, small jar of it in the cosmetics aisle where you find ointments, topical vitamin E bottles, night creams) helps seal the threads. I also pull or push on the bleeder valve and will find a sweet spot where the vacuum is best when Mityvac (bleeder) is running.

I replaced my rear bleeder valves. They were rusty where you connect the tube and making poor contact. They are a different size than the fronts. I also put beeswax on those new threads. I've had those bleeders rust so bad on another car I had to replace the caliper.

Good luck