Prius Gen 2 stumbling, cold start rattle, running lean? Blistered spark plugs, pinging when hot

I have an issue that seems to be getting worse and has gotten annoyingly worse after new plugs and throttle body clean.

Has always seemed to ping a little under load when at operating temp and slight/moderate acceleration. Didn't think much due to many other cars doing the same.

Then started to rattle on cold start, stumble/shake.

Recently changed plugs and cleaned throttle body a little (in situ). Old plugs all blistered. Cleaned pcv valve. Seemed to move ok?

Engine start shake seems a little harder, and it's revving high when coasting down or low speed idle, slowly coming down at complete stop.

I did a battery D/C.

No codes from my OBD2 Bluetooth. It's old but has shown a misfire before when there was a tiny bit of moisture in one cylinder.

Any thoughts or other things to check? I guess I could clean the maf though it didn't seem very dirty looking at the temp "football" thing in there