Recently I've created multiple 'rooms' in Telegram w/o any intentions of adding another person. Each room has a theme so that my notes are segmented. Also I have access to Google Speech Services, so I moved away from voice recordings completely. Instead, I dictate my notes, which are automatically turned into text. Works for a couple paragraphs, but if I were taking recording work meetings, I'd probably use Google Recorder
I use Nextcloud. But that also means setting up and managing Nextcloud. By the same token you could use google drive.
For notes and photos you can export them within the app. Notes specifically requires that you print and then hit the share on the print dialogue to save the notes to the file system as a pdf.
Notes also has another option: if you have a non-Apple mail account on your phone - you can enable notes for that email account and simply move (or copy) your notes from one account to the other. The notes will then become available within that email account mailbox structure on any device or machine where that email account is enabled.
For voice recordings you can save any voice recording directly to the iOS filesystem.
The iOS files app also allows you to connect to any other server/desktop via SMB.
There are lots of options here. None are awesome, but they work.
In short it’s a way to share network access to storage across MacOS/Linux/Windows.
MacOS switched from AFS to SMB (as the default file sharing / network storage protocol) a few years ago as it was clear that was how everything was headed - though iOS and MacOS also have native support for NFS.
On linux, you can use samba to create SMB shares that will be available to your iOS device.
It’s a lot of configuration though - so maybe not the best choice.
As for Nextcloud - indeed you can use it in your local network without making it available on your WAN connection. That’s how we use it here.
When we need it remotely - we VPN into our home network. But no exposed ports. :)
You can share it to your iCloud drive by clicking the (...) icon next to your active recording, select share [↑] and select "folder". You will then be able access it through your browser https://www.icloud.com/iclouddrive/ as a MPEG-4 audio file (.m4a).
You might need to activate the iCloud drive before hand in your account/icloud settings
No you can Share to whatever other Platform you have installed, but every iCloud account has 5GB of storage so I suggested it. You can also share to a discord / matrix / WhatsApp / Signal contact if you prefer
I'm not an iphoner, but I think you will, one way or the other, need some sort of intermediary. I personally host nextcloud, so that would work. I've heard good things about syncthing, but haven't tried it myself. Signal allows sending yourself messages and has a desktop client that you could use.