There's a local map, but it's like a weird dot matrix that shows off elevation and shit and has no detail at all. I get what they were trying to do with it for uncharted planets, but it makes absolutely no sense for cities and outposts because it offers absolutely no information.
As for the locks...yeah, basically.
There are...four? levels of lockpicks. I think it's novice, advanced, expert and master.
You can pick novice without leveling, but advance, expert and master you can't pick until you select the perk in the lockpicking tree.
Each level of lock adds additional levels to the lock.
It's not so much more difficult, just more tedious/time consuming. The best way I could describe it is if you had to pick an additional lock with each level of difficulty in Skyrim or Fallout 4.
And it's absolutely pointless since there seems to be no modifier to high level locks when it comes to giving you better/more items. Looking up on the starfield subreddit, most people are claiming they find more EMPTY containers after lockpicking master locks than under the lower levels.
It's a baffling choice. It's like they're combining Oblivion's lockpicking system with Skyrim/Fallouts, but they don't gel well at all.