Dude, Let's plays were my crack as a child! It was very fun watching people play old retro games that I didn't know they existed until now. I also didn't know how to emulate games properly, so that probably helped a lot lol. Many of the LPS I watch were from Brazilian people however, since you know, I couldn't speak english when I was at the age of 10.
However, I did watch this Kirby Super Star co-op LP when I was at that age. It's definetly a relic of its time, but idk, I always have very fond memories watching it.
(Them talking about how Kirby Super Star Ultra is about to be released makes me realize that 2008 was really 17 years ago, which then makes me a little sad.)
My favorite playthrough that I'm very autistic about is a Fire Emblem Conquest playthrough made by my boy Deltre:
Every part is a hour long (with some reaching almost 2 hours), so I'm not sure if I can recommend it, but the way he plays the game by using fun/bad units but also playing very hyper efficient like a LTC is so entertaining to me, his commentary and the way he dubs cutscenes have also made me laugh a lot of times.
Sadly, neither these people make content anymore, but still, I shall forever be grateful on what they posted.
I will also still stand by
chuggaaconroy's original Earthbound Let's Play, I haven't watch him since but I can't imagine he has aged well.
I only started watching Chugga in 2018 when funnily enough, he remade his Earthbound Let's Play, and I found it very enjoyable. He feels like a tour guide that loves his job a bit too much, explaining every little tiny detail about the game, be how to beat it or just random trivia, and I was all for it.
I don't watch him anymore, but that's mostly just because my life has been pretty busy lately.