If you want to support free software, open standards and fight monopolies you should choose Firefox on iOS, too. However take into account that it may work a bit slower and consume a bit more battery than Safari on iPhone. The reason for this is not bad work of Mozilla, but monopolistic practices of Apple: https://docs.house.gov/meetings/JU/JU05/20190716/109793/HHRG-116-JU05-20190716-SD036.pdf.
So FF over the DDG browser app?
I can’t say anything bad about DDG browser, so if you like it, you should probably use it. The only reason to use Firefox I can suggest is that Mozilla has more experience in web browsers…
I concur with the suggestions above to create a ‘cheat sheet.’ I have a file where I keep the Linux commands that I do not use often enough to remember but are useful sometimes.
One thing to be careful of: Linux distributions want to change little things here and there. When you do a search on how to do or fix something, always include ‘debian’ or the graphical interface in the search. Otherwise, you’ll get suggestions on other distros or GUIs that implement things differently. Those files or settings may not exist on your system, etc.
I use it. It seems to be reliable enough and I don’t have any problems with performance or battery drain.
Ironically, I started using it because Safari was driving me mad, locking up all the time. The underlying problem is probably long fixed, but now I still mostly use Firefox on my spiPhone - until my Librem 5 arrives …