I recently got Tubi and I love it. If you don't have it then get it. It is a free streaming service (free due to commercials), but it does have a lot of older shows and movies. As someone who loves pre-woke British stuff they have a lot of that as well.
They have some anime and that is how I saw Fist of the North Star. I really enjoyed it. I am wondering was that based on a Manga or was it a totally original movie? I'd love to get more stuff related to it. Any recommendations for similar anime?
If you want more Robotech, the real version is Macross and there's 7 different series under it. Macross is the original (including the Macross Do You Remember Love movie). Macross Zero is good. Macross Plus, and Macross II Lovers Again I haven't watched, but seem fine. The rest lean much more into music/idols, including Macross Frontier which is good. I haven't watched Macross 7. Macross Delta has good music, but I stopped watching because idols standing on jet wings while they dog fight was too much.
For just older sci-fi:
Akira is a classic movie.
Dirty Pair (1985) is a comedic show about 2 female mercenary problem solvers. They have a high success rate, depending on how you interpret it.
Planetes (2003) is a show about people clearing debris orbiting earth.
It's been way too long to recommend, but you may want to check out: MD Geist (2 movies). Venus Wars (movie).
Thanks!