Question about Samsung Galaxy S21 Ultra EE Enterprise Edition EU

An Enterprise Edition model that has the Google label for Android Enterprise Recommended (AER), these devices are usually suitable for enterprise and management because they are certified by Google, and these devices also receive Android security updates for longer (until January 2021).

So in principle, it is an advantage to buy an AER-certified device. This model from another manufacturer also has this label and would also receive Android security updates until January 2026 and also the update of Android 12, 13, 14 and 15, but would also be somewhat cheaper and have twice as much built-in memory:

Xiaomi 12 5G (256 GB, Grey, 6.28 ", Dual SIM, 50 Mpx, 5G)

Ok, thanks for the info! Am anything but an expert, but I love big displays and high pixels, like 3200x1440, as I'm older, and even with reading glasses I can't see everything perfectly on small screens when I game....
And this is what the Samsung S21 Ultra has, but with 256 GB massively more expensive than with 128 GB, unfortunately.

Many thanks for the expert information!
Regarding the built-in memory, is 128 GB "normally" enough, or what do I need more memory for?
I need my smartphone for whatsapp, and Angry Birds, plus calendar and camera, otherwise for nothing special... Should a memory of 128 GB be enough for me, or will it be rather tight?