Google Analytics initially evolved from Google's purchase of Urchin Analytics, an Apache log analyzer. That's why legacy Google Analytics property IDs all begin with UA-. The familiar ?utm_ keywords that can be tacked onto URLs to track referrer statistics in Google Analytics are remnants of Urchin Tracking Modules.
All these years since Google initially purchased and overhauled Urchin, they built a from-scratch, much more robust analytics app, Google Analytics 4, also known as GA4. Much to the chagrin of every Google Analytics user everywhere, GA4 is not backwards compatible, incredibly confusing and bulky to use, and all users are being forced to upgrade by this July.
I completely get Google wanting to start over from scratch with something that's more robust and efficient. I really do get that. I also get that it's not practical to maintain both independent systems simultaneously. I get the need to migrate all users off of a legacy platform and onto the new platform. What I don't get, and what infuriates me to no end, is that Google can't figure out some way to import all of the data that its users have been collecting over the past nearly two decades into GA4.
So ends my rant.