What the title says. I recently had a crash during one of my runs, and I was wondering if I would be able to restart Minecraft if it does crash, or would it just invalidate the run?

I believe the team have allowed people to restart their game if it's unplayable for one reason or another, so there should at least be a chance of getting it accepted. It would help if you were doing desktop capture and the crash actually showed if it's a really good run, otherwise sending them your .minecraft/logs and .minecraft/crash-reports folders would probably be enough if you open a ticket on the discord.