I like tech, old and new, so:
https://www.youtube.com/@CathodeRayDude
https://www.youtube.com/@TechTangents
https://www.youtube.com/@ConnectionsMuseum
https://www.youtube.com/@VeronicaExplains
https://www.youtube.com/@UsagiElectric
https://www.youtube.com/@PlatimaTinkers
https://www.youtube.com/@RetroBytesUK
https://www.youtube.com/@harkeofficial
I"d also suggest Jeff Geerling but he’s close to a million subscribers.
About trains, cycling, transit, and urbanism:
https://www.youtube.com/@OhTheUrbanity
https://www.youtube.com/@BenDurham
https://www.youtube.com/@MilesinTransit
https://www.youtube.com/@JagoHazzard
https://www.youtube.com/@TFTSB
And about hiking, camping, outdoors stuff:
https://www.youtube.com/@StephenJReid
Oh and on languages and etymology:
https://www.youtube.com/@WordsUnravelled
https://www.youtube.com/@RobWords
https://www.youtube.com/@Xidnaf
https://www.youtube.com/@kklein
https://www.youtube.com/@Linguisticae (in French)
https://www.youtube.com/@Linguriosa (in Spanish)
He says it himself
Life is worthless unless you can profit out of it. If saving that species in that place would be profitable, then it would be worth it. But it’s just a worthless fish without any value. That’s what life is worth for him.