Firefox startup flag (Regolith 2)

[brzezinskip]

Hey! I want to change to firefox from Chrome because I wasn't able to get hardware acceleration support to work on chrome. Now, I do have FF startup under mod shift enter, but the problem is, I'd like to add a startup flag so that I can choose which profile to open the browser with. I know there's a command that allows for it which would be firefox -P but I'm unable to set it up. Any help appreciated.