It wasn't optimized, but that doesn't mean it was waste. You built the muscle memory and now you're learning to apply it. Unless they taught you actively bad form, so long as you were training it should help, and you'll have random 'aha' moments where you realize things you did on the bags are translating to sparring.The new school is so much better in the sense of wacht technique drills ends with 5 rounds of 2 minutes sparring. I do 3 technique drills a week and 1 heavy bag.
Is it all waste that i did train first 10 months only 4 sessions a week heavy bag? Out of those last 6 months 1 session technique drills with 2 rounds 0f sparring.
Now new gym since 3 april switched to much more technique drills. I feel i should have switched much earlier
At the very least, it has helped you with cardio, and learning how to punch i a way to conserve your energy (even if you don't consciously realize, your body likely made those adjustments)