Law enforcement departments have probably already looked into this, but some sort of instant, non-lethal, immobilizing foam that instantly hardens on the suspect, would be very effective in keeping him from squirming around and reaching into his waistband for something. Better than a tazer.
There has to be something else that works. We are at a crisis level of the public ignoring police orders and fighting the cops, either the perp ends up dead or the cops.
If somebody could invent something that would disable a non compliment suspect then they would be as wealthy as the person that comes up with the COVID-19 vaccine.