for me, the button doesn't show up :/

[rapus95]

And I have no clue how to troubleshoot. Can you help?

[CKextreme]

I used this script today and it still works with Chrome as browser.
Did you tried Chrome and maybe to use without script blocker (e.g. ublock origin) and maybe try with Inkognito Mode if possible (Hint: extension needs to be enabled manually for Inkognito Mode)