You can for sure be above average without a very good memory if you're good at spotting tactics. But average isn't a super high bar.

Define "average" and "very good" - it's quite easy to become good enough to beat all your friends and family (as long as you haven't made friends at the chess club or chess competitions). But if you want to do your best at the local chess competition held in a school hall at the weekend against all kinds of people, from little kids to pensioners, then yeah, you're going to need to spend lots of time studying openings, learning end game theory, and solving chess puzzles.

Have you tried Chess960?

I am very decidedly above average (1800ish on lichess) and my memory is blank.

Memory helps but another way is just to play the best moves every turn based on the position.