Macs with Apple silicon and Macs with Intel processors and T2 chips always use full disk encryption, irrespective of the FileVault 2 setting. Enabling FileVault 2 on a Mac with Apple silicon or with T2 changes (improves) how the keys are managed, but does not change the use of full disk encryption. Platform Security, page 92

How are you testing for df, when troubleshooting? Logged in via Terminal.app, or via a Java app? Checked for any surprises in PATH? Used whereis or such to go looking for the df executable? From Monterey 12.6.2: $ whereis df df: /bin/df /usr/share/man/man1/df.1` Is full disk access enabled for the Java app, and for Terminal.app?

#import <UniformTypeIdentifiers/UniformTypeIdentifiers.h>

Set ai_family to AF_INET for IPv4 addresses, or to AF_INET6 for only IPv6, and try your tests again?

In addition to the (excellent) reply above... Only macOS has command line tools. Not iOS nor iPadOS. And macOS fully supports C functions and Objective C classes and methods. Same as do iOS and iPadOS.

IPv4 17/8 is Apple. I've not seen an official published listing of the IPv4 or IPv6 addresses used for app testing.

Postscript support was removed in Ventura. View .ps and .eps files on Mac - Apple Support

Swift, Objective C, C, etc., it depends rather more on what the daemon is going to be doing. Docs: https://developer.apple.com/library/archive/documentation/MacOSX/Conceptual/BPSystemStartup/Chapters/CreatingLaunchdJobs.html https://developer.apple.com/library/archive/technotes/tn2083/_index.html#//apple_ref/doc/uid/DTS10003794 pmset is the usual command for accessing this info, I don't know off-hand if there's an official callable interface. Here's a semi-recent version of the pmset source code that's part of the Apple open source: https://opensource.apple.com/source/PowerManagement/PowerManagement-1132.81.1/ The Apple code is written in Objective C, and hasn't changed in a while per the comments.

See if your storage is simply saturated. RAID-5 doesn't scale at all well, both around ever-larger disk sizes and failures, and around apps with higher write loads. Current RAID-5 trends are toward inevitable secondary and catastrophic failure during RAID-5 recovery from an initial error too, as the overhead and risks of failures arising during recovery from the initial error is higher than many might even realize. Try some tests with other storage with equivalent file counts. I've been migrating all RAID-5 to RAID-6, or otherwise migrating from RAID-5 to more and bigger HDDs and RAID-10, or RAID-6 SSD. Some reading from ServerFault: What are the different widely used RAID levels and when should I consider them? PS: RAID is not a backup strategy.

Nobody here can answer that, short of reverse-engineering the app or reviewing the app source code if available, and not even really then. Whether it’s “safe” depends entirely on the app and the app developer. Both the safety of the app now, and across future app updates. This app is clearly hooking in oddly and deeply, or is otherwise doing something unusual. Disabling SIP is not something I’d do for anything short of a critical app from a well-regarded and trusted developer. There’ve been too many problems due to apps that have “burrowed” into macOS over the years, too. Malware, and system add-ons. That’s all part of why SIP exists.

You’ll need to connect to a Mac as part of Enabling Developer Mode on a device

Best to contact Meta support for assistance with Meta Facebook apps and services, and for other issues with Meta products and services, and ask them for assistance with this.

Update your Mac to macOS 12.6 (macOS Monterey current) and try again? Failing that, update Xcode to Xcode 14 (current), and try again?

Try a Time Machine restore of the Keychain files in ~/Library/Keychains and restoring those into different filenames for access? More likely to work: restore your entire Mac from your Time Machine backup immediately prior to the errant deletions.

There isn't one best, as different folks have different requirements. Weight, screen size, numbers of I/O connections, etc. Visit an Apple Store. See the alternatives for yourself. For web development... Review the recommended configurations for whatever Web development apps and frameworks you prefer. If you're editing HTML and JavaScript in vim or emacs, you won't need a fast Mac. if you're using some more complex process, you'll need to account for those apps and requirements and likely increases over time. As for app development... Xcode requires lots of memory. 16 is minimal for that, and—with occasional exceptions—I'd expect Xcode memory and storage requirements will increase over time. If you're working on larger web or larger app development projects, you may or will want a larger internal display, or a connection to a larger external display. Budget for at least one external HDD of 4 to 6 TB for backups. You might want or need an external keyboard, mouse or trackpad, maybe a spare cable and charger for a second location where you might routinely also work, USB-C to USB-A adapters or a dock, a satchel or messenger bag or other carrying case, or other add-on gear in addition to the external backup storage. For Mac with Apple silicon more generally: minimally 16 GB memory and as much internal storage as you can afford, as neither can be increased over the lifetime of any portable Mac Apple is currently selling. And if you don't absolutely need mobility with your Mac, the desktop Macs can be a better value—I've worked with various folks that wanted and bought portables, but always used them on the same desk.