I feel the same way. It's like we're back to the MS-DOS era where every application had its own interface and you had to learn each application's way of performing tasks. macOS and to a lesser extent Windows prided themselves on consistency across applications. But this required developers to voluntarily conform to those platform's guidelines, and in the case of Windows, the goal of consistency was challenged by (1) Windows' backwards compatibility and (2) Microsoft's own disregard for consistency at times, such as Microsoft Office using its own UI toolkit instead of relying on the UI elements of the version of Windows Office is running on (for example, Office 97 introduced flat toolbars, a different style of menu bar, and the Tahoma font, which deviated from Windows 95/NT 4 and its button-style toolbars and its use of MS Sans Serif); this theme even carried over to Windows NT 3.51 where Office's UI was out of place; see
http://toastytech.com/guis/nt351word.png for a screenshot). Contrast that with the Web, where there are no common UI/UX guidelines. Sadly this philosophy has spread to the desktop, where increasingly each application seems to have its own UI/UX without regard for the platform's guidelines.
There is one good thing I could think of about the loss of consistency across applications: the underlying operating system matters less when the application works the same across platforms. Ironically this may help with the adoption of desktop Linux; Chrome, Slack, Zoom, and VSCode generally work the same. To paraphrase, this fulfills Netscape's vision in the mid-1990's of reducing the operating system to a bunch of device drivers.
One would think that Microsoft and Apple don't want Windows and macOS to be reduced to a bunch of device drivers. Then again, perhaps Microsoft's and Apple's business models don't require the long-time maintenance of these desktop-oriented operating systems. Microsoft makes a lot of money from Office and Azure, and Apple makes a lot more money from the iOS platform than from the Mac.
Still, I personally lament the rise and triumph of the siloed app, and the decline of platforms that promoted UI/UX consistency through a set of standard human interface guidelines, and I feel personal computing is generally getting worse instead of better.