BTC89LS400

So I originally had 3 codes, P0440 P0441 P0446, with a P0325 knock sensor being new but easily identified. However after replacing a broken hose and purge sensor, 2 codes are left over, P0440 P0446.
I’ve been googling answers and getting listings with the original 3 codes instead of the 2 left over. Do I just have to disconnect the battery for a moment to reset the codes?

Also, for the knock sensor, I plan on replacing it myself with along with one of my mechanically smart friends to replace the knock sensor, since auto shops think I'm made of money. However, I'm curious to what specific brand I should use. Should I stick to OEM Lexus or also replace the knock sensor harness encase that's causing the issue? And I hear that once you remove the intake manifold you have to clean off and replace the gasket, what's the best recommendation for that?

911LE

Use the oem knock sensors. As for the intake gasket it is a painted steel shim gasket and usually lifts right off with no residue left behind. If it leaves some paint on the surface I would clean it brake cleaner and a rag.