I'm a returning player who stopped pre horizons and have a PSA for other returning players who might not be familiar with landing on planets:
You can't land on 'landable' planets (those with the blue arc) if they have an atmosphere and you don't have Odyssey.
I post this because I spent good few hours trying to figure out why I kept 'dropping too close' when trying to land on what I understood to be a landable planet. The tutorials I had watched were apparently all pre-Odyssey and they all said you could distinguish landable planets by looking for those with the blue arc. Apparently the first planet with a blue arc that I tried landing on — over and over again — had an atmosphere. <shrugs>
I post this here with the hopes that others may quickly find it if they run into the same issue.