You can add a bookmark shortcut button with the address about:profile and that makes it more accessible. I added a key shortcut to the bookmark itself. Then I can use cmd + L to focus the address bar, type the letter p, and hit Enter. That opens the profiles page and it’s reasonably fast.

I also created a similar bookmark with a JavaScript snippet that removes fixed elements from the page, typically top bars. I now have it in my muscle memory.

the portable version is also an option if the user passes a location as the profile path. This can be made more convenient by adding shortcuts for each profile.

The UX could definitely be improved, but it's manageable in my opinion