Lexus LS500 2018 P3003 and P3006 with long cranking time when warm

I have a Lexus LS500 2018 with 47k miles. It has two issues:
1) When engine is warm (if left for 45 minutes to 4 hours), it takes 3-4 seconds longer to start and some times I see some dark smoke from the exhaust for a bit. I have changed spark plugs and maintenance for the injectors but no change and mechanics gave up on this but it still bugs me.
2) I got check engine light two time. I have techstream so I could extract the data list at the time of misfire (it is cylinder misfire - cylinder 6 and 3). It seems that trim is negative on startup when it is engine control is on open loop and directly injected. I am attaching the stored data and a picture of A/F data on engine startup.

Spark plugs were replaced by original ones and injectors were inspected and found ok. Fuel pressure is ok as well.

I would really appreciate any guidance as I have left this with many workshops without any successful resolution.

you can try swapping #6 coil with another good , like # 5 cause your coil could be going bad .when hot

I like what Lupe said about the coils. You can swap them around and see if the miss moves. I think I'd also put a fuel pressure gauge on this one and see what happens. It sounds like the injector(s) might be leaking down when it's hot. That would lower your rail pressure at start up and load the cylinder with fuel. If you don't have a gauge you can also try cycling the key a couple of times before you start it and see if it fires up quicker. It'll still miss if the injector is bad but if it starts right up it's probably because the rail pressure is low from a leak, most likely an injector(s).