Is there a protective cover for this?

Yes

According to reviews, the performance is good for the price. Unfortunately, I personally have not had any experience with whether the device works for image reproduction in drone control. Nor have I found any reviews from others who would write about it. With a bit of luck, someone will get in touch who has tested this and can tell you their personal impressions.

yes, to max. 256 GB. That's what it says in the specifications.

Android 8.0 Oreo

The matching ones are listed under the accessories: Huawei MediaPad T5 (10.10", 32GB, Space Gray)

In any case, according to the following page, this is currently planned (December 2019): https://www.getdroidtips.com/huawei-mediapad-t5-android-10/