InDesign Freezing Despite System Meeting Requirements

Task Manager shows plenty of "breathing room" for your hardware, those background agents, specifically Huntress Rio and the RMM Agent are notorious for being overprotective. Because InDesign is constantly writing small temporary files and auto-recovery data, a security agent trying to "scan" those files cause a file-locking conflict, which looks like a hard freeze to the user.

Beyond those agents, keep an eye on those CEPHtmlEngine processes. Those handle the "Home" screen and various interactive panels. If one of those hits a snag or tries to dial home to a server that isn't responding, it can occasionally hang the entire interface. A quick way to test this is to disable the "Show Home Screen" option in your General Preferences.

Another "invisible" culprit that wouldn't show up as high CPU usage is a corrupt font or a broken network link. If your project is trying to pull an image from a cloud folder or a server that’s lagging, InDesign will often sit there "spinning" while it waits for a response from the Windows file system.

If you want to rule out the software itself, try a preference reset by holding Ctrl+Alt+Shift while the program starts up. Reinstalling usually keeps your old (and potentially buggy) settings files, so a fresh reset is often the only way to truly start from scratch. If the freezes stop after disabling those security agents, you’ll just need to add InDesign to their "allow list" so they stop breathing down its neck.

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Best way to test if it’s InDesign or something on the computer causing is to start your computer in Safe Mode and try the files again - if it’s not lagging then it’s something that’s interferring with InDesign. 

You can start in normal mode, maybe try eliminating different tasks in the tasks manager see what frees up the error.