>Just think of all the random tech debt that could be resolved if devs had 2 hours a day to code anything, including new projects that benefit everyone.

regardless of the potential benefits of this plan, zero tech debt would get erased.

imho net tech debt would increase by the 80 20 rule, meaning that you're not going to get more than 80% of the side projects fully wrapped in the 20% of the time that you've allotted to them.

I guess tech debt could even be increased in some cases. Some people shouldn't have too much time available :-)