Greasy Fork

The script worked perfectly for months but since the new changes to Youtube's interface, it no longer works for me.

Sorry to hear it no longer works for you. Currently it is still working for me in ViolentMonkey on both Firefox and Chromium browsers, and that's after I also recently experienced a Youtube UI change making homepage tiles bigger. I know Youtube sometimes do A/B testing where they change things for some users and not others so it may be a case of that, or something else. I can't really do any investigations into this whilst it still is working for me, but if it eventually stops working for me also I will look into it at that time. (Although the further Youtube go in removing the feature the harder it will be to restore and may ultimately become impossible).

It is only partially working for me. I'm using Brave (browser) and TamperMonkey (extension), and the script doesn't work for the first four rows of thumbnails. Everything after the fourth row works as intended.

Also, disabling the "Shield" and re-enabling it makes the script work for all rows including the first four. I think the script isn't running until after the first four rows are loaded, meaning they don't get the script effects, only the rows after the fourth, and I don't have the tools to debug it.

I'll see if Brave can download ViolentMonkey and, if so, test the script there.

UPDATE: After extensive testing (lasting like 10 minutes as I just disabled and re-enabled TamperMonkey and ViolentMonkey (and this script in both)), I have come to the conclusion that maybe TamperMonkey is bugged, as the script works perfectly on ViolentMonkey, but not on TamperMonkey.

I've recently tried to replicate in Brave and Tampermonkey v5.3.2 but afraid I can't reproduce the issue, still works here currently. I'm not sure what to suggest other than you might have to keep using Violentmonkey to run this script for now.