Lucidstuck II

Seeing as we have floor plans complete with marked guard routes, I don't think a radar is really all that necessary. But what would be fantastic is a way to subtly see through doors, vents, around corners, and potentially walls (though we probably wouldn't need that).

Something like this would suffice.
https://www.amazon.com/Vividia-Portable-...industrial

Notably not drawn on the map are placements of security cameras. The Obsidian star is locked behind a keycard door, so we can logically expect cameras to exist in this setting. Something we'll need to be on the lookout for. Whenever possible we should scout the inside of a room before entering.

A radar might/might not highlight the existence of cameras, but a snake camera will let us subtly see anything that's visible in a room before we enter it.

Security cameras would also imply a room with at least one guard monitoring the feeds. Possible rooms include two rooms on the ground floor and the room with the keycard on F1. A security office strikes me as a location likely to only have one door... so my guess would be the room with two guards on the ground floor. Take out whomever's watching the cameras then we can ignore the cameras. Possibly wipe the records on our way out.

Considering that I'd suggest we check that room with the two guards in it on G from the other side of the southern door as it's a quick way in.

SpoilerShow

Circled doors/vents are critical to scope the room ahead before entering.

If it's a security office we'll need to take those guards out to negate the cameras otherwise we can go with the route Xoleuph suggested. Though we may have to find a way to deal with cameras regardless.