But a rogue can move 90’ in a turn, if they dash with their action and their bonus action. Or they can move 60’ and attack once in a turn, where others can only move 30’ and attack or 60’ and not attack. Or move 30’, attack, and try to hide, or move 60’ cautiously enough not to provoke an opportunity attack. Basically any combination of action and cunning action results in the rogue traveling further in 6 seconds than another character could while performing the same activity. The natural interpretation (IMO) is that the rogue can simply run faster than everyone else.
Yes, the Rogue on the whole can run faster than another character... but that doesn't necessarily follow that the individual segments of the Rogue's turn have one segment moving faster than the others, does it? Look at it this way... a character's 6-second turn can be divided up a couple different ways:
1) The two or three things a character does in their turn all occur simultaneously over those 6-seconds. So for instance one PC can do a move and an Action at the same time with both taking 6 seconds to complete... while another PC can do a move, an Action
and a Bonus action at the same time with all three taking 6-seconds to complete. Which then means the latter character might be faster or better at "multitasking" as it were-- being able to do three tasks instead of two in a similar amount of time, but those three acts taken are all still equal in duration with one not being faster than the others.
2) The 6-seconds of a character's turn gets divided up into segments and each of the move/Action/Bonus action takes up a certain amount of segments within those 6-seconds. So one character might take 1 second out of their turn to move and 5 seconds out of their turn to take the Attack action... while another character would take 1 second out of their turn to move, 3 seconds out of their turn to take the Attack action, and 2 seconds out of their turn to make a Bonus action attack. In
this case of how we interpret things... yes, the Bonus action attack indeed was "faster" than the Attack action.
But that only causes several questions/problems for us. First... the latter character's Attack action has ALSO gotten faster just because they took a second attack with their Bonus action-- it went from 5 seconds down to 3. Which begs the question then how do we know that the Attack action
only drops 2 seconds down to 3 seconds total? Who is to say that the original 5-second Attack action didn't drop to 2 seconds long, while the Bonus action attack taking up 3? Which means the Action was now faster than the Bonus. Or what if in truth in the original scenario the move takes 3 seconds to complete and the Action takes 3 seconds to complete... but when you throw in a Bonus action, all three now drop to 2 seconds long each? At this point, the Action and the Bonus action take the same amount of time and the Bonus isn't faster.
We don't know. The game doesn't define it. So there no definitive rule that tells us that a Bonus action absolutely takes less time to complete than a regular Action. We can certainly
interpret it to be faster if we want, certainly... but even just above there are other ways to interpret things as the move, Action and Bonus action all taking equal time-- either because they all take 6-seconds and are done simultaneously, or they each take a 2 second segment of the full 6-second turn to complete. Who's to say who is right?
But this is all just splitting the finest of hairs and has no real matter or care in the grand scheme of things. At the end of the day, it's all going to come down to how the OP's DM chooses to interpret the rules themself.