Having trouble uploading bulk asins for brand story

I created my brand story using the new shoppable one. I’m having trouble getting my asins to upload and work though. I have over 1000 asins and it just goes into bulk upload but never really does anything after that. So I broke it down into smaller segments to upload. So my questions are:

Can you do a bulk upload with over 1k asin numbers?

If not can I do a bulk upload of a smaller amount and then upload more to that same brand story, or it seems what is happening when I try is that it is overriding the ones I do have in there.

So for example I made a smaller file of 175 and did a bulk upload and that worked. Now I want to add 250 more to that brand story. It seemed like it just overwrote the 175 and did not add to it. So how do i add to it? I can’t do them all manually.

And if there are errors do I need to go in and remove those asins and then resubmit without any errors? I was hoping it just wouldn’t add the errors but it seems to be making it stuck in limbo if there are errors or the file size is too large.

I can’t seem to find any info on this online and am getting frustrated more than normal with this : ) Thanks!