> Can anyone suggest where I’d find longer tracks?

Check OpenGameArt Music[0] collection.

And if you need a background for too long videos just use those tracks which are "loops"[1]

[0] https://opengameart.org/art-search-advanced?keys=&field_art_...

[1] https://opengameart.org/art-search-advanced?keys=&title=&fie...

An easy way to get long ambient tracks is use Paul Stretch on literally any audio. Try taking some royalty free track and paulstretch it to 2 hours in Audacity.

My always go-to site is Jamendo. An active community and really great music.

Freemusicarchive is the place where a lot of people typically get music. You can search by license, genre, length, etc.

Better Music on Audiak :-)

how do you figure? audiak appears to have only a handful of songs, mainly of the same genre and not necessarily well composed, and no way to search or otherwise make use of it in a serious way without just listening to them all

archive.org the net label scene.