This might sound crazy but I have one giant .md file with an entry per day with notes of whatever I was working on.

Days are divided with (-) character like:

-----------------

At the start of each day I just write a list of todo's and check them throughout the day.

I then copy them to the next day if not completed.

Have been doing this for several years now. I always keep it open as a tab in the IDE.

Will periodically truncate the file and archive it to avoid getting to big.