Does every issue need to be attached to an epic, though? A simple, well-described bug can be enough on its own, I think? You do need to regularly go through the backlog to re-order it, remove outdated tasks, combine duplicates, etc. for it not to become unwieldy.
My/our approach can be summed up as:
- if it's code-related, however small, it goes in the backlog, with or without an epic, and it follows the normal flow of things. We have weekly reviews where we maintain the backlog, basically.
- if it's not code-related, I personally have a markdown document, where I plan stuff day by day. It started out as a simple way to document the stuff I did so as to not forget anything in the daily standup. But now I routinely use it to jot things down a day in advance or in a special 'must not forget' section. It's proven to be very useful in remembering those little things people ask you throughout the day without jumping on them right away. The bonus is I have a very detailed archive of everything I did spanning literally years by now.