Everything Dies When I Go to Start SOLVED!

Hello all,
I finally have the Crusty Biscuit at the body shop for paint! Everything was working fine up until I went to start the car to drive it up on the trailer.
Here’s my issue:
I turn the key on without starting and everything works; the fuel pump starts priming, Holley sniper display turns on, and the compressors for my air suspension system turn on. BUT, when I turn the key to start the engine everything dies! I can’t get anything to turn on immediately after that but if I wait a couple minutes it will all come back on like normal.

I haven’t done much to troubleshoot the problem but here’s what I have done:

Charged battery overnight, it reads 12.2 volts on my sniper efi display

I tried jumping the starter relay but that won’t get the starter to work

Checked and tightened all power wires and grounds

I feel like the issue is starter related, I recently removed the starter wires to install a heat shield on them to protect them from the exhaust. It worked fine several times after that but of corse when it’s show time something decides to goof up!