No, they don’t, but if you want to mark a particular location for yourself (like a trading post for instance) so you can always find it, then scan the building. You’ll always be able to find it on the ships navigation screen and visually as a white horizontal line on the horizon. You can do this for up to 3 locations I believe (to clear scan from space I’ve heard). Handy for if you are spending a lot of time on a planet and going far a field.
As for the galactic map, well you can either follow the waypoints that will lead you towards the centre, or you can use free view which will allow you to navigate to any planet, though whether you can warp there is another matter entirely.
It’s probably easier to build Antimatter.
Yep. If you don’t have the formula then go to a signal tower and use a bypass chip to scan for colonial outposts, this should reveal manufacturing plants , and you’ll get material formulas when you bust in and sort out the issues. just don’t get killed by sentinels and save before you do go in so you can roll back in the event you don’t get the commands right.
Personally I’m a huge fan of getting monoliths etc done first. Being able to understand what the Aliens say is a massive bonus. I know about 400+ words of Korvax now and it’s paid dividends with all the interactions in terms of figuring out what needs to be done.