I think that one of the hardest things about daily writing is simply continuing to find good ideas for your content after months and months of writing every day.
No matter how good of a writer you are, you will eventually struggle. If you're not a pro, then it's going to be even harder.
One thing you can try to do, aside from constantly exposing yourself to new content, reading and exploring new ideas, is to use the small things, the trivial ones that are happening in your life as inspiration or, at times, as main subjects for the articles.
For example, I recently wrote a post in which I talked about a piece of software I found on Linux called "KDE Connect" that allows you to link two devices such as your phone and laptop and then share certain things between each other or control some things remotely.
I was looking for such a tool for quite a while, so I was quite happy that I finally found one, and because I thought it was very good I decided to share my discovery in an article.
Is this something I usually write about? Not really. But considering that I've been writing every day for almost 7 months now, and that finding new ideas gets harder and harder, I decided to write about the software.
This might not result in the highest quality articles, but if your goal is to post at least once a day then using the small things that are going on in your life could help you achieve that goal.
You got a new job that you find interesting? Talk about the experience and talk about the things you like and you are excited about. Watched an interesting movie that you loved? Talk about it and what you liked. Read a good book lately? Write a short review.
Not all the articles you write must be revolutionary. Use whatever you can get to be productive.