I don’t really understand your question, but I use Google Tasks stand alone for reminders. You can also launch Google Tasks through the Google Calendar app.

For example, I get a daily reminder for medicine. All my reminders show up as a different color on my Google Calendar also.

You can also group the task reminders by user created categories.

Depends! is your 15U global?
in terms of camera, I don’t use UW at all so I don’t care. main camera seems fine but little temperamental on xiaomi. and 100mm telephoto very similar to the x200u. BTW, xiaomi 70 mm lens is underrated in my opinion, i took some nice pictures with it. Also I don’t like taking pictures in very dark environment, so I try not to.
In any case, they both are similar hardware, proc, memory, etc. you just test the heck out of them and use what you like. I checked a lot of video comparisons, but in reality it should not matter much.
BTW I like xiaomi 2 color design. but like you probably will get x200U to check. X 15u global has far more 4g and 5g bands as well. so consider that too.