How can I tell if I am being misinformed?

Changing head gasket because I had white smoke and coolant in my oil.
Took my cylinder head to the first machine shop and I was told that it needed everything done to it. (Valve guides, valve seats, surfaced, potentially new valves). Cost was going to be $800.00 or so. I was told by this place that 12v Cummins cylinder heads “are cast iron so rarely will they crack, and they don’t recommend crack checking because it is pointless”
I decided to order a cylinder head online but long story short that didn’t work out.

Now I have my cylinder head at another machine shop and I brought my engine block as well because I realized my number 1 cylinder was deeply gouged throughout the walls. All of the other cylinders still had crosshatching and before my head gasket blew, I had zero blow by.

This shop tells me that I need a whole new cylinder head. This shop claims is cracked and that all of my cylinders need rebored to.020 over. The one cylinder obviously needs this and then all of my others (which still have crosshatching) apparently are “too close to being out of spec and you would practically rebuilding a used engine”. I wanted just to get cylinder one bored and then sleeved to STD specifications.

This is a slot of information but essentially my question is: ‘if an engine has no blow by and still has crosshatching then what exactly is worn out to where I would need newly machined cylinder walls?’
I am obviously not a machinist, but I have been told to always “Trust but verify”.
Other than checking out my injectors for correct function I have not done anything to this truck's engine, I do not know it’s 355,000 mile history besides that it has a different turbo, head studs, and different injectors.
Any insight or guidance would be greatly appreciated, thank you for your time.