Yes.

I learned React and later React-Native. Selling myself as a "mobile consultant" then worked fine, nobody cared "how" I made these mobile apps.

My idea was the same with back-end, learning some framework and start selling myself as "mobile cloud consultant" or something, with the hopes that clients also don't care "how" I create these cloud back-ends.

I know SQL, worked most of my time with RDBMSs, so this wouldn't be big of an issue. As I said I already did a few back-ends, but my focus was on front-end, usability and such.

I just mentioned DynamoDB because I had the impression that it was "the AWS DB", do they offer an SQL service besides Redshift?