Hi having bought my ls430 just before lock-down, I've spent considerable time and money to rectify similar issues.
After cleaning the oil from my throttle body, I managed to replace both rocker cover gaskets, spark plug oil seals, PCV valve, rubber grommet and inlet connection pipe (all for under £50 off Amazon).
With fresh oil, plugs and filters all round (£150 from Lexus) this has all but removed my engine smoke on startup and full acceleration.
Hope this helps!
By the way, later I replaced the coolant temp sensor, installed refurbed injectors and remapped ECU too - what a difference!
