I never buy phones from carriers, always directly from manufacturers, so no idea. Manufacturer bloat can be deleted pretty straightforward.
My primary use case was magisk to enable taking screenshots from otherwise protected apps. Was living in China for almost 7 years, and even though I speak it quite alright, reading is a whole other level. And there are quite a few apps there that I had to use on a regular basis that had this damned flag_secure enabled so I couldn't otherwise take screenshots to run them through a translation app.
The second one was system level adblock, since the alternative is for adblockers to install themselves as local VPNs routing traffic to 127.0.0.1; however being in China meant I actually had to use a real VPN to access the free internet, and I certainly didn't want to choose between ads or privacy. The latter still applies; I'm using a VPN on most days.
Lastly, being able to use magisk also gives me access to some advanced security apps such as Hibernator (freezes apps, meaning they are basically uninstalled and reactivated on press, so they can't use data, don't get updated etc.), Storage Isolation (lets you configure on a per-app basis which folders it might access), App Ops (advanced permission management, which also includes an ignore function that acts like as if a certain permission was granted, but would feed random data or zeros to the app).
Being able to uninstall everything including system apps is also nice, though that can still be achieved with adb. Browsing root folders when looking for specific data is also nice, but I used that twice in about 5 years, so it's probably not essential.
Luckily most devices work perfectly fine without internet. And I get the convenience of being able to switch on the heating or lower the window blinds and stuff from the office before leaving so that it's nice at home, but we did that back in the 90s with a simple timer.
Same for my dishwasher. I don't even understand why that thing asked for a wifi connection in the first place, it's not like I can remotely unload it or anything. And a notification is perfectly useless when I can just check my watch...
With playcurl next I didn't experience any issues yet, it's polling a new device fingerprint every couple minutes to make sure your device never ends up on a blocklist, and you can trigger this manually in the magisk app as well.
Can't guarantee it's never going to be blocked if Google changes the algorithm, but that would just mean they have to adjust the fingerprinting as well.
Nah you can easily bypass play integrity on a rooted phone, see my comment above.
With a rooted phone you can install Zygisk (magisk + zygote) and then a bunch of modules that simulate system integrity.
What you need are "play integrity fix" and "playcurl_NEXT".
The first module lets you bypass the google play integrity check, the second one will download updated integrity fingerprint files every 5 minutes to ensure that the bypass never fails.
If you know how to install custom ROMs, this part is not a big challenge.
Just keep it offline and get yourself a Nvidia shield as a multimedia station. They are excellent.
Wait a second, iOS is chock full of garbage that you can't uninstall whatsoever. At least on Android you have a chance to get rid of everything.
So you pay late and complain that the landlord insists on his part of the contract? That's delusional.
I don't know anybody buying those crappy carrier deals, to be honest. They had a place and time in the early 2000s, but beyond that they seemed to die out mostly. Maybe still a thing in the US, no idea.