Studying and working hard is a good solution. Honestly Excel is NOT easy if you want to use it for more than basic spreadsheet. I’d take a class ASAP.

Did they not ask you all this on the interviews? Like did they not ask what kind of stuff you can do? Did they not give job description? I’d say it’s on them then.

Another option is to ask if they have lower level positions if you aren’t ready for the higher one? Or maybe a different role?

In a meanwhile maybe I’d keep an eye open or something else what might be out there.