As I see it, the degree in itself is a plus, but the grades aren't that relevant for a pilot job. Even if it's a III, it's still nice to have. Myself, I got a II-1 back in the day. Nobody ever paid any special attention to it, I think. I don't think I would have been anyhow better off now with a I or worse off with a II-2. Those marks mostly matter when applying for postgraduate studies or a grad scheme, definitely not when applying for a pilot job.
I still seem to more or less remember what does one study to call themselves an engineer. Quite a lot of it is a nice brain exercise and a bonus to your general knowledge, but totally irrelevant to a pilot job. Like, how much computational fluid dynamics do pilots do in their day-to-day lives? Or are there any line integrals up there? So, a lot of the academic content you went through will never serve you in the flight deck.
I believe that your basic maths and physics are good enough if you made it into final year of engineering. So, you won't have any trouble getting an ATPL. There are plenty of stressful things out there for you now, please don't make your degree class one of them. Everything will be fine.