Something that would be helpful is the ability to be able to have an assortment of highlighted text colors available when you create a note in a sketch ("//"). This way, it's easier to re-find areas of the code that you still need to work on.
Select the text you want to highlight> right click> highlight> highlight color.
The texts of comments help a lot to remember what was done,
But perhaps the best way to avoid too much research is to separate the code into parts, each sector of the program can remain in the file, and so the IDE will show the tabs.
So if for example your code has Webserver, ArduinoOTA, TFT display, FFT etc, it might be nice to split the code.
Splitting into multiple files (https://community.particle.io/t/splitting-into-multiple-files/22693/6):
I'm trying to split a program that compiles as a single file into separate files (to try and reduce my brain load a bit!).