[bluegrass]

Much of what you've listed is simply the cost of maintaining a 100K mile vehicle.
Though some of this seems like bad luck, as I'm surprised engine mounts and radiators need replacement.
If you want to save money, start by DIY'ing more tasks...all fluids, spark plugs, brake pads, tire rotations.

You are also WAY overdoing the oil changes...every 3K miles with expensive Mobile 1 is completely unnecessary.
Follow the MM system (every ~7K miles) and buy the cheapest 5 quart jugs of name brand oil you can find at Amazon or Walmart. I've put upwards of 190K miles on vehicles using this approach with zero issues.

The overarching issue is the fact that you bought used.
These costs are why used vehicles are often a poor value vs. buying new.
Buying new would have almost certainly been a better LONG TERM value (total cost / total years of ownership).
Your truck had all of the best & cheapest miles already used up. You bought it when the more expensive maintenance is coming due, without the privilege of using it during all of the earlier cheap/trouble free miles.

 

[bluegrass]

Did your new 2019 RTL have sliding rear window, nav, Bluetooth, tow pkg, etc etc.
I think I looked back in spring of 2018 and new comparable was going to be much more than $33000 on the road. But maybe my memory is not right.

I also had a 2019 RTL I bought in late 2019. I paid $31,250 including the dealer doc fee.
After sales tax and license fees, the total OTD came to $33,400.

It had everything you mentioned (sliding rear window, bluetooth, tow pkg, AWD) except navigation. I don't know why you'd care about in-vehicle nav when you have much better nav on your phone.

You get a brand new vehicle, with full factory warranty, that requires very little maintenance for the first ~75K miles.

As 17BE noted, this is why the new vehicle (when negotiated properly) is a considerably better value, over the long-term, than most used vehicles.

 

[bluegrass]

In my case, it sounds like my out of pocket for the new model would have been just shy of $9000 more.

I purchase vehicles the same way @17BE described above and highly recommend it if you care about deriving the maximum value from your vehicles.

Given the numbers you mention, buying new would have been a much better value.
I've posted this calculation elsewhere, but it helps put the new vs. used decision in perspective.
Adjust the mileage assumptions to suit your use case.