I used to own a Galaxy Tab S3, and it became horribly slow (a Samsung Galaxy S9 Plus released just the next year in 2018 was faster) after barely more than two years of use. This isn't an isolated case, as there are threads on Reddit documenting slowdowns (with more recent models) due to software updates [0][1].
In contrast, users report the iPad reliably lasting at least 5 years without noticeable slowdowns [2]. There are surprisingly few other Android tablet alternatives aimed to compete with the iPad (especially the iPad Pro).
This makes the iPad the only option for a high-end tablet that lasts years without upgrades. There are also other benefits of the iPad (e.g. better stylus with the Pencil, better variety of apps in the App Store, less buggy apps from the App Store), but these can be considered as reasonable tradeoffs in favour of an Android tablet (no walled garden). However, I personally don't believe that the short lifespan of the Galaxy Tabs make them a reasonable competitor to the iPads.
[0] https://old.reddit.com/r/GalaxyTab/comments/mzwzew/s5e_slow_...
[1] https://old.reddit.com/r/GalaxyTab/comments/od1f4v/galaxy_ta...
[2] https://old.reddit.com/r/ipad/comments/m4013a/how_long_do_ip...
