Whenever I see lists of top science fiction anime I feel like the vast majority of the given shows aren't even science fiction. Unless all it takes to be science fiction is to be fiction and have some science. Maybe so and I'm just being a bit a snob, I don't know. I'm open to discuss the matter.
Anyway, here are some of my favorite science fiction anime. I'm curious if anyone else has some favorites that I have maybe never heard of.
Legend of the Galactic Heroes
This is likely my all time favorite scifi anime. It's quite long and the list of characters quite extensive which isn't my usual forte, but there is just something so comfy about this show.
Blame!
This is a bit of a weird manga to say the least. There probably aren't many manga with less dialogue. Regardless I still feel like I took an endless journey across a structure of a scale I can barely comprehend.
Space Battleship Yamato 2199
Regrettably I have not seen the original, but this more modern remake seems to be true to the classic style.
Royal Space Force: The Wings of Honnêamise
A visually beautiful movie with all hand drawn backgrounds and animations. A tale about a group of individuals who have a dream of building the first rocket ship to make it to space.
I think I only saw the Blame movie. How different is from the manga? I don't mean the story development of course, it's a 10 volume manga adapted into a 2 hours movie. What I mean if it really follows the same plot and (part of) the story of the manga or it's more like a one-shot story in the same universe? I don't know what about the movie made me think it may be the latter. Anyways, it was interesting enough to give the manga a chance but I always forgot. Thanks for the reminder.
Also, I'm a little surprised, given your list, not to see Macross. It's an absolute classic for a reason and I haven't seen all the sequels but they're not bad at all and most of them have good reviews.
The plot of the Blame! movie is almost non-existence in the manga. Some elements of it are in there for sure, but I would not consider it even attempting to adapt the manga. But at the same time it doesn't really matter due to the nature of the manga. Which is basically Killy going on an adventure over an indeterminate extremely long period of time across an indeterminate seemingly infinite distance. Since his adventure is basically endless the events of the movie could conceivably happen at any point in the manga.
So the only problem with the movie is that it ends. Which means you don't really understand how endless his journey is.
I've also just never seen Macross. The art always looked beautiful, but I've never picked it up because I didn't understand the concept of the singing in a sci fi setting. I'm sure I would enjoy it whatever is going on, but I've had endless other things to watch and read.
I get it about the singing. While the sequels get a little weird about that, on the first one, it's actually pretty straightforward. The Macross ship gets far away from Earth using faster than light alien technology, but then they need to go back to Earth at regular slower than light speed while also avoiding attacks from the same aliens trying to conquer Earth. A lot of the episodes are about how the crew is struggling to endure the trip and losing hope of finding a safe planet back home, so a culture outside the military duties is formed, with restaurants, services and entertainment. The main singer is just part of that entertainment and becomes the favorite idol aboard the ship. The concept of music doesn't exist for the aliens so in a couple of occasions her songs are used as psychological warfare. That's it.
I also get having a never ending list of things to watch, anime and other things. But if you ever get the chance, at least the first series is totally worth it.