As Head of Engineering I'd say that's a pretty decent set of skills, but depending on how well you are doing your job, that is underpaid. The best advice I got go en was: to get promoted make yourself redundant in your current role and indispensable in your new role.
There are many ways to that but that's another topic.
Don't underestimate the value of a jack of all trades. I have an engineer like you and he's getting raises because I can give him anything random and he gets it done. Not great on the tech documentation but that's where your skillset seems to compliment someone like him in a team.
Don't pick a lane for the sake of picking a lane. Know where you want to go. I'm a jack of some trades - but you don't need speciality if you want to manage people and teams. It's a huge amount of fun to be able to co-ordinate and see specialists in action.
On the flip side specialisation can be rewarding in its own right... as long as the FOMO of other stuff doesn't eat you away.
Lastly, talk to your line manager about your salary. A good manager will be open to discuss and will appreciate it.