I was going to advise the viewing of the playlist of
Kerbal Space Program videos on
Scott Manley's YouTube channel. If Quill18 is any good, Scott Manley is probably good as well. He has places in the game named after him, I think (as a major backer on KickStarter), and an IRL asteroid named after him. He is from Scotland and has a degree in astrophysics, IIRC, but his employer is Apple, where he works (in California) on stuff he can't talk about. I think he's a U.S. citizen now. He's big into rocket technology and has many other science and rocketry videos available on his channel.
If you find you prefer Quill18 over
Scott Manley for
KSP, those other science/rocketry (current and historical) videos are sure to excite you. He knows his stuff and his videos are for the nerdy crowd, so expect more meaningful comments below his videos than after the videos in most YouTube channels. He makes really professional-looking videos, with superb visuals to accompany his narration about a topic, including looks at historic NASA tech and that of other countries. He also follows and summarizes, after the fact (usually within a day), current launches and development of new commercial rocket tech used by SpaceX and Northrop Grumman and Boeing and others who still have a finger in the launch-from-American-soil pie, as well as launches, successes, and failures by NASA/ESA and other countries, all with superb video accompanying each point he talks about (where it exists... the last big launch from India showed the Indian mission control screens for a few seconds and focused mostly on the people behind monitors who were looking up at the screens and their expressions and periodic clapping, which made it hard to guess what was going on with the spacecraft).
Scott Manley also has a series on
What Kerbal Space Program
DOESN'T teach, which goes over elements of rocket engines, rocket fuels, and various other details that occur "behind the scenes" in KSP so you don't have to know minutiae or have multiple degrees in Aeronautics, Design, and Rocket Science to successfully make an in-game space program work.
Oh, and there are videos in which Scott has gotten together with real astronauts to fly
KSP ships into space. But I've teased his channel enough (can you tell I'm a fan? Most of the quality videos and summaries and detailed explanations are only 10 or 20 minutes long, but some are longer or shorter.
Wow! I just noticed that Scott now has enough subscribers (or whatever the requirement is) to qualify for his own custom YouTube Channel URL (I might be confused, if that's always been the case... a slight variation on his preferred name Syzygy)! He has 1.13M subscribers and 2,345 videos as of the time I'm typing this! That won't occur for quite a while more (sequential integers in his video count... not until 3456? 2468 will come much sooner, but that's just sequential even integers).
KSP 2, which is in development at this time, I think, will require a beefier PC+GPU to run it because the visuals will be more realistic, and, I think, will have more of those minor things that
KSP necessarily glossed over. I can't remember details other than the improved graphics and better physics simulation. (Some of those things can be added to
KSP via community-developed add-ons, but there's still a limit.
KSP 2 will go beyond that limit inherent to the way
KSP was developed in the Unity engine, which cannot simulate some things in as fine a detail as would be required to better-represent physics of extraterrestrial bodies and orbital mechanics/dynamics.)
KSP does a great job at doing what it does, though. It's an excellent product.