We use Trello, but any simple cards-and-lanes service would suffice. You need at least 4 columns:

Backlog, blocked, in progress, done

You add cards to backlog, and self-prioritise. You provide access to the board to someone who has the say in your company, so they can reorder and comment and so on. You periodically review the order - perhaps something you just did makes it easier to accomplish one of the other cards, say. You always just pick the card off the top, put it in "in progress" and work on that. If you're pulled off because something else is of higher priority or you're waiting on some other person or process, move the card to "blocked", add a comment as to why. Pick the next off of "backlog" or "blocked" (if you can) to go into "in progress". When you're done with a task, move the card to "done". Perhaps set up auto-aexhive so that cards older than, say, 3 months in "done" are archived (still available, but not cluttering the board).

Sorry if I'm just explaining what you already know or do. This is just what I'd recommend for "eating the elephant": organise your bites and tuck in.

Classify all the tasks with an impact / ease score from 0-5. Multiply the numbers together to understand the relative priority of each item.

It won't be perfect but it will a good place to start.

You also do this at a product level instead, and invest all your time onto one product to begin with. This might reduce your switching costs working between projects/products.