I'm glad you liked it! Apologies for making it so long. 😅
I can adjust his background per your recommendations!
I used https://pathbuilder2e.com/. It includes an option to export the statblock. I see now that unfortunately, it's missing details. I'll be happy to recreate his sheet via mythweavers proper.
I based the Morningstar on your heavy combat rifle homebrew, but yeah, the general gist is heading towards it eventually dealing energy damage. An eventually transforming railgun is perfect!