Check out Mullvad Browser. It’s created in partnership with the Tor Browser, but optimized to be used for the Clearnet. You don’t need to use Mullvad’s VPN with it either.
I’m stuck on Joplin personally, but have you taken a look at Standard Notes? I think it checks all your boxes.
Oh dang, you’re right. I used to use StaxRip back when I was doing more encoding and then finish with MKVToolNix, but I think the gui is Windows only.
Probably should have recommended Handbrake.
AAC is higher quality for the same compression level and generally preferred by Apple. MP3 should be fine too though.
EDIT: To be clear though, the programs I listed can handle all kinds of codecs including AAC and MP3. fre:ac is also good for ripping CDs if you’re into that sort of thing.
I’ll have to check it out. If you want to listen to Audiobooks specifically, I will say that the Open Source app BookPlayer has been fantastic for me.
If you really need to convert the files to something like AAC for native iPhone playback, I would suggest either fre:ac (audio only) or MKVToolnix (video and audio).
Installing VLC on your iPhone is probably the easiest solution. It should play the Opus files without any transcoding needed.
My small concern with Librewolf is getting security updates quickly. Cool project though. As I understand, the team has been better about quickly patching security vulnerabilities in recently months too.