Hi
I've had my Clara HD for some years now. Now it's lagging a lot. Turning it on, browsing or shifting pages is slower now, it doesn't react as fast or direct. But the real issue is that marking parts of text takes for ages to save, up to 20 sec. And since it does not mark sometimes exactly the text I want due to the finger not pointing exactly on the correct word or line, I have to edit the marking.
This is now really frustrating.

I removed all books that I had read, just keeping around 20 books. After buying it several years ago, I installed nightmode, nickelmenu. What is causing it to slow down? I assume it's using most of the RAM, and that's why it's so slow. But why, or is it something else?
And most important, what can I do? Do I have to make a factory reset? I am no so keen on doing this, since I would have to install and make nightmode work again, which was hard the last time.
Please, any tips?