Thanks for info. However a bad fuel pressure regulator will cause the starter to stay engaged on the initial start up. The regulator holds the pressure and overnight when it sits it slowly looses pressure causing the engine to turn more because it’s buliding pressure/prime. After the initial start the vehicle will start normal because the pressure isn’t being lost that fast because vehicle isn’t sitting that long.
I think it is the way you worded it that was misleading.
You having to keep the starter engaged longer is the EFFECT of the engine losing prime from sitting overnight. It is not CAUSING the starter to remain engaged longer, you are having to hold the key in the start position longer to get the truck to start. YOU are causing the starter to stay engaged longer because it's not starting like normal.
When I first read your post it sounded like the starter pinion wasn't retracting properly (staying engaged) and i thought your starter needed to be replaced.
If you think it is the pressure regulator try this.
When you get in the truck for the first time in the morning DON'T turn the key directly to the start position.
Instead turn it to the RUN position and listen for the fuel pump.
After the fuel pump shuts off turn the key back to OFF and wait a couple seconds and turn the key back to RUN.
Again listen for the fuel pump and when it stops turn the key back OFF.
Again turn the key to RUN and this time when the fuel pump stops turn the key to START and see if it fires up easier for you.
Following the process I outlined above you are priming the fuel system and if the regulator is the problem them this should help.
