2012 Tundra - Flex Fuel - Ignition issues?

2012 5.7L with Flex Fuel with 150k miles. However, I never use flex fuel.

It has a brand new battery, old one confirmed dying. CCA had fallen off drastically.
Also replaced fuel pump/module with new Delphi unit.

After it's been sitting, 4-5+ hours, it cranks and sometimes it'll start in a few seconds. Sometimes it'll turnover, almost sounds like there is no spark or no fuel, until it stops. Again, next time I hit the ignition it'll start and sometimes it'll take a few more attempts.
If it's only been sitting for a bit, it'll start right up, zero issues.

Runs perfectly fine once it starts too. No engine light.

What else can I check? Could it be coil packs or plugs? Best way to check them?
Something else in the fuel system?