Improve database tools / reduce limitations

I have to load a new collection monthly.
I usually get this failure at least once:


With a respectable connection:

PROBLEM:
(1) Where is bulk remove for collections?
“Select the same file” as the error message suggest does not work - it causes duplicates.
Deleting collection items with code is ridiculously slow - 50+ minutes for a few thousand items.
The more reasonable option is to make a new collection - but you soon run out of names that make sense, due to the failure mentioned above (data upload to wix server fails).

(2) Why the limit of 10,000 items per collection … at a time?
It’s 2019 - why such a low limit for this strange “speed-bump” that slows developers down unnecessarily?

REQUESTS:
(1) Add proper database tools, at the very least bulk remove.
(2) Write a better IMPORT client - keep moving packets until complete.
Study best practices as observed by other download managers.
(3) Remove arbitrary limits, or at least increase such limits (50,000) ?