If the create mods with the steam 'n' rails addition and the gun mod (with framework) are in the same mod pack minecraft fails to start, displaying no unique errors (ones that are not present if starting with the mods one at a time (steam'n'rails ones' lol)) if starting using a launcher with a console

I believe I am encountering the same issue. With a custom modpack with both Create: Steam n Rails and Crayfishes gun mod, when trying to load Minecraft it goes to a white screen and refuses to load any further. If touched, it stops responding and crashes. I found I could sometimes get it to load by either waiting a while, or re-launching it until waiting worked. After a while though, this method stopped working and Minecraft just refused to load up. I tried downgrading Crayfishes gun mod, but it still wouldn't load. I haven't yet tried removing Steam n rails to see if its exactly the same problem, but I thought I'd mention it here.

I tried removing Create: Steam n rails but Minecraft still wouldn’t load up. It might also be some other create addon.

I doubt that this combination causes said issues. I have a modpack with a lot of mods including Create, Steam 'n' Rails, around 20 or more Create addons, Gun Mod, even with some addons, and many many more (Forge 1.19.2)

It is for certain that combination, I am trying to run a small modpack and assumed it was a few other mods, but I could only get it to launch when removing Steam n' Rails AND Big Cannons, something is very wrong with create addons and Crayfish's Gunmod