Greasy Fork

It took 'a minute' to understand what exactly this was achieving, as the snapshot is not very informative...

Considering I use a simple style (within userContent.css) to force ALL links to have an underline:

/* Always make links underlined ~ https://userstyles.org/styles/25056/always-make-links-underlined */
a[href] { text-decoration: underline !important; }

this made its usefulness very clear; and like you, a globally-set color (red) for all links.

Gave the script a try and - wowza! - yes, very useful! (see attachment; I don't know how to inline images)

Did youtube ever have this styling before?

"It took 'a minute' to understand what exactly this was achieving, as the snapshot is not very informative..."

I know. It isn't easy for an image to convey the fact the there is now a link where the was none before.   :)

By default, when not adding a userstyle, the link color of the new link in the recommendations changes on mouse over:
 - from gray to black in light mode
 - from gray to lighter gray in darkmode

Then when visited you can color it with my userstyle, or you can target the classname css selector ._chan_lnk