I think it's the best choice.
Google is locking down its apps to certified devices, see here
. Make sure whatever you buy is certified by Google otherwise you won't be able to sign into your Google account and thus lose any functionality that depends on it, eg. Calendar, Gmail, etc. This is especially relevant for phones whose main market is China, (excluding brands like Huawei, Xiaomi, etc who have a significant global presence).2.
I have phones that are years old, Huawei, Samsung, Nokia, Xiaomi, and now Motorola (Lenovo). They all still work.
I bought a Homtom HT16, (made by the reasonably well known Doogee), it was cheap, it had good specs for the price, and it worked for what I wanted to do. It has stopped working after 14 months, no longer turns on, no longer charges ... effectively dead.
This is OK because I don't live on my phone, I don't care if people can't contact me on it, they can still send an email or ring my landline.
You use your phone for business so you should be looking at reliability above all else.
The Umidigi S2 Pro apparently only has four 4G bands, (FDD-LTE
: 800/1800/2100/2600MHz ... no TDD-LTE
) ... this was the first thing you checked, what bands and topology your provider uses, right?
Just as an aside, don't expect any upgrades to the next Android version on an MTK based phone ... be surprised and happy if you do get one but
never expect it.