You have strong soft skills and ok math skills, be an engineer
I have been doing civil engineering for the past 12 years, you are vastly underestimating the value of the skills you have presented.
In the US (and presumably everywhere else) Engineers have to wear A LOT of hats. We have to complete technical calculations, develop technical drawings, we have to write technical reports. It's all very technical. When you are a junior engineer, this is a huge part of your job. If you're not the fastest, that's not necessarily a problem as your billing rate isn't as much as the project manager's, you're there to learn how to do the process and what it means in the grand scheme.
But as you get past the junior engineer part of your career (2-4 years), you start finding out what our real job is. We balance budgets and evaluate costs, we talk with clients, find out what they need and explain how that can be achieved, we meet with members of the community and explain to them how and why the project works. In summary, the rest of your career is focused on taking the technical information that you (or your subordinates) created and making it accessible for non-engineers and it is the single most important part of the job.
- If the client is a municipality, they're often very concerned with project cost, so it'll be important for you to explain to prepare an engineer's estimate (technical skills) and explain to them what their available funds will actually get them (non-technical skills).
- If the client is a private developer, they may have a strict timeline they need to meet and are willing to spend money to meet that goal. You will need to reach out to all the parties with permitting authority for your client's project and find out how quickly they can respond to permit applications. Knowing who to contact will be a combination of technical and non-technical skills as you'll need to discuss the project with the client and determine exactly what they want to do (non-technical skills), identify what permits would be required for that project (technical skills), reach out to permitting authorities and figure out how quickly they could respond (non-technical skills), figure out where overlaps occur and identify a critical path (technical skills), and then present the whole thing to the client in a way they can understand (non-technical skills).
To summarize, your soft skills are what will make you a good engineer. Taking technical information and making it accessible is the single most important thing you can do as an engineer. Some engineers are are only good at the technical skills and their careers peak very early, you can only do the calculations so well.
Other engineers possess strong soft skills and become project managers, client managers, vice presidents, and CEOs of engineering firms because they have the skills to convey their technical knowledge to the world. They may not be the best in their company at the technical skills, but it doesn't matter because they understand the technical information and can explain it. Furthermore, they don't need to be the best because someone else in their company can do the technical work for them.
I think you may have what it takes to go far, you just don't see it yet.