Bob didn't get the character he wanted out of character creation. The GM should have helped Bob create the character he wanted to play.
So, Bob went into character creation expecting to get a character who would be challenged by high-end gunplay and not worried by the cyberpunk day-to-day. Instead, he created a character who would not be challenged by high-end gunplay, but would be worried by the cyberpunk day-to-day.
Something obviously went wrong there, whether it was Bob's lack of familiarity with the system (character creation or otherwise) or just a character creation system with poor player guidance from the jump.
And in a more general sense, Bob should be comfortable straight-up telling the GM what he wants to get out of the game, and the GM should be comfortable helping Bob create a character that behaves as Bob would expect of them. The exact reason why is going to have to wait, because first we need to talk about why Bob's impulse didn't work out for him as well as he'd expect.
How Cyberpunk Do
There certainly is a Shooty McShootenstein in your average cyberpunk universe. A savant with firearms whose transportation, provision, and intrusion needs are all provided for so he can focus on the thing he does best, murder other human beings with guns, and never be bothered by everything else. Just the way his corporate masters want it.
The kinds of characters PCs are expected to make, on the other hand, are cyberpunk protagonists, people who won't or can't fully participate in corporate society and as a result have to develop a more broad skill set. They're outside the support structure of corporate society that can cover for being a more narrowly skilled person. Not only that, but the corporate society forcibly imposes the chaos and hazard it doesn't want to deal with on them, either indirectly because their only meal ticket is Mr. Johnson at HappySmile Ltd who wants to make some bad PR for a competitor by hacking one of their self-driving toxic waste trucks, or directly because somebody hacked a self-driving toxic waste truck and it jackknifed into their squat and now everyone and everything they care about is at risk.
What Bob wants to make is a freelancer who's survived for a decent time in this environment and, in addition to cultivating a personal specialty in the care and use of firearms, developed that broader skill base but not to a distinctive degree -- even if sometimes it's just "knowing who to ask", that's still got to be developed as a personal relationship and not an entry in a corporate directory. So the day-to-day isn't an issue for Bob, and he can still be challenged by high-end gunfights against the Shooty McShootensteins of the world, though his role in them might not be so much to absolutely outshoot the Shooty as to engage the Shooty for a significant length of time while other associates work to dump more chaos on Shooty than he can handle.
Shooty McShootenstein can certainly be a cyberpunk protagonist, perhaps after he's been discarded by his corp in favor of the shiny new v2Shooty model, but the thing is that weaknesses are at least as dramatically interesting as strengths. As such, a natural part of Shooty's cyberpunk story is going to be about the day-to-day challenge of dealing with all the chaos and hazard that he was insulated from by his coddled corporate life, which is exactly the stuff Bob doesn't want to have to play out.
How GMs Do
But it's also important to talk about why Bob should tell the GM what kind of play experience he wants to have, and why the GM should help Bob make a character who will have that play experience. At its core it's about being a good sport.
Being a good sport means that the GM is generally very restricted in what they should do, as compared to what the rules say they can do. They generally have absolute narrative control over everything outside the player characters and can, in fact, drown the world in nuclear fire any time they want, but sporting GM conduct means that you don't threaten the PCs with impossible obstacles but with dramatic ones (or at least impossible obstacles with dramatic workarounds).
Players generally have fewer restrictions, at least compared to the scope of their possible actions. The GM is expected to adjudicate any reasonable course of action the players come up with, and sporting player conduct usually only means avoiding options which are in the rules but regarded as flawed somehow, such that the GM can't fairly adjudicate them.
Because the scope of player action is so wide, the scope of expected GM reaction is also similarly wide and often falls outside the GM's session prep. As a result the GM often has to work out an appropriate next step from first principles, and usually what they work from is their understanding of game canon, in this case cyberpunk canon, even if that's just limited to the setting flavor and play examples in the rulebook. They have to improvise the next step in the story, and that's much easier to do if they can pull a fitting obstacle from the entirety of the cyberpunk day-to-day instead of having to come up with a reason to have an even more shootier guy show up.
So it's also sporting conduct for the GM to help Bob create a character that performs as Bob will expect in the game as the GM will run it.
Final Notes
This all, of course, assumes that the GM understands how to fairly represent the challenges of the cyberpunk day-to-day in mechanical terms, and how to use the character creation system to create a sort of "baseline freelancer" who's capable of dealing with all of them. Ideally the system itself can create those sorts of characters without the GM having to worry, but if not, the GM needs enough understanding of the system that they can create a character template for people like Bob, who wants to be a baseline freelancer with a specialty in firearms.
