Greasy Fork

Doesn't work. Firefox portable 116 + Greasemonkey.
Extra "button" don't appear.
I tested on fresh (clean) Firefox distribution.
Do you want extra information?

With Tampermonkey works fine.

Greasemonkey are unsupported

Greasemonkey dead
Greasemonkey 4.0 is a new addon, just same name
it has many bugs, poor compatibility, and maintenance stopped