I've tried that sequence, and found it incomplete. On the local Big Sur Mac, I needed another step. Image Capture and other accesses were still rejected with the same "you do not have permission to open the application "Brother Scanner", and with the scanner error -21345 shown. After deleting and reloading per the above—and that Brother file deletion link seems to omit the Brother scanner software files located over in the Scanner directories—I also needed to change the permission on a hunk of the Brother scanner code to world read and write (!?), as was described here: https://discussions.apple.com/thread/252991431?answerId=255657775022#255657775022 ⌘I on that Brother scanner file, unlock, open up everyone read and write, and Image Capture started working.

TCP, UDP, QUIC, SCTP, etc., are all transport protocols built upon IP (IPv4 and IPv6) packets. IP and IP routing is underneath all of what you are asking about. You cannot extract and send just the UDP or TCP packet contents in isolation; the packet you send is IP (IPv4 or IPv6), and that IP packet then contains TCP or UDP or QUIC or other transport contents, and which then contain the application data being transferred. Start here: https://en.wikipedia.org/wiki/Internet_protocol_suite

$2000 and a month seems way too cheap for a custom app with the requested features. Not with any accuracy for the speech-to-text, and not with the required media playback and handling and positioning features. This app is something I’d expect to pay “enterprise” pricing for, too. Related: https://www.techradar.com/news/best-speech-to-text-app

You'll need functional (private) DNS within this network, as well.

From the Linux docs: “The gethostbyname*(), gethostbyaddr*(), herror(), and hstrerror() functions are obsolete. Applications should use getaddrinfo(3), getnameinfo(3), and gai_strerror(3) instead.” Per the IEEE Std 1003.1, 2004 (POSIX) standard docs: “The gethostbyaddr() and gethostbyname() functions may be withdrawn in a future version.”

If this case should arise again, one of various similar tools: https://downforeveryoneorjustme.com/

FWIW, I'd look at both Xcode and Swift Playgrounds app here. Xcode is great and all, but it's also a complex and intimidating behemoth. Learning with the Playgrounds app particularly if also learning the programming language—and Apple would prefer that language to be Swift—as the developer can focus more on learning the language and less on the IDE tool.