I’m not sure if these will help, when I listen to instrumental stuff it’s usually just a (personal) productivity thing.

David Bergeaud (Ratchet and Clank (1) OST) (some of the other games too, but for me less so the newer stuff games that have more action-movie orchestral music) (listen also: Spyro OST, different type of groove)

On the other hand, Journey for Tuba - II. Ballad has that mystery/free-roaming sound at the start (listen also: Bully OST)

I also like radio.garden with my local NPR stations (2 channels, often classical and jazz, so if you want to skip news… not always instrumental though) also ouch. There once was Radio Riel (in Detroit, MI), but it doesn’t currently work on garden, they seem to have changed names. You might want folk or reverie, depending on what’s playing. (though is non-english voice an instrument?)

The Over The Garden Wall OST is good, but not all instrumental. I did find an instrumental version, so maybe? Also, this is an autumn vibe.

For more game OST stuff, maybe something from Oddworld (if you can appreciate the atmospheric without it seeming too dreary), or Tomba is more cheery. Maybe even the Sims (Sims 2 is cheery and complex, Sims 1 is simpler, also there seems to be diff music for PC and consoles).

You probably could also go even simpler than instrumental, for instance searching ‘piano solo music’.