> Maybe it's your algorithm

Nope, its just the set up of Youtube.

The front page is by design around 60% videos you have already watched. Best case scenario.

It used to be 9 videos in 3 rows of 3. now its 2 videos, then 5 shorts.

In the side bar the default was "Related" which was almost always new videos, directly related to the video you just watched. Now its a tab called "All" which aggregates related tabs such as "Watched" which again is videos you already watched. Content from the same channel (not necessary related to the current video)

All of this hides possibly related videos and narrows down discoverability.

it also ignores the push of youtube to reduce visibility of things (the front page being mostly shorts by volume is pretty telling)