My first couple of oil changes on my 2003 I did and then switched to Mobil 5000. Then around 100k started using Mobil 1.
I know a couple of fleet guys that had to use conventional in the fleet trucks due to cost. These were construction trucks that were loaded down daily and did not have an easy life. The only issue they had were 6.0s with piston slap.
Another fleet was for a large lumber/logging company that were used by timber buyers and plowing out logging landings. Fleet guy was a family member and was ecstatic when they switched to Mobil 5000. They were using whatever was in the bulk bin prior to that and it wasn’t consistently the same oil due to price. No breakdowns on engines or transmissions in the trucks which were all half tons with 5.3s. Their older trucks had 5.7s in them.
If I was OP and had his truck I’d use conventional and take a sample at 3k and post it up here just for fun as long as he’s not short tripping a lot and continue until 5k if the sample is good. You won’t know until you try. He also said he’s used synthetic since new until he used the blend and it quit leaking. Run the blend and go on with life or don’t.
You also suggested to a member here to not tow with their pickup until 10k miles were on it. That’s pants on head type advice.
