Greasy Fork

What's the secret ritual one must do after installing the script and verifying it's enabled to have the buttons reveal themselves in the latest version of Chrome? MAGA?

Probably your setting prevents it from working.

> third party cookie is disabled

> Obviously, I have third party cookies disabled (like everyone else).
--- By default, Chrome setting chrome://settings/cookies set as "disable third party cookies in incognito mode". If you set "disable all third party cookies", this userscript will not works or it need upgrade for this case. You may disable access to localStorage (in JS, line 17-48) from site spmbt.github.io, where settings of this script are saved. This part of code must returns your fixed settings, if no access to //spmbt.github.io .

For more security you may use browser Brave with this allows of cookie from list of trusted domains: https://greasyfork.org/ru/scripts/7543-google-search-extra-buttons/discussions/12468

Edge allows you to trust specific cookies too. Click the blocked cookie icon in the url bar, click "site not working," click "show cookies and other site data," then look under the "blocked" tab. spmbt.github.io should be there.