Cannot download > Export all files as MP4 quality, only separately

Hi, I'd like to download a 41-page document with animation as one, complete MP4 video file. I have two issues:
1) I get single named mp4 videos of each separate page. This is annoying, it is easy to convert them https://www.adobe.com/express/feature/video/merge?linkId=100000379857172 but still I am surprised I have to do it manually.
2) More importantly, I need to export 4k quality videos because the video is being used on a big screen, and also I noticed that on the default custom resolution the kerning between some letters was incorrect. I cannot choose "4k" when I want to download all pages, it's greyed out. Can anyone suggest a solution other than me downloading 41 pages one by one? 
Here's a view-only link: https://new.express.adobe.com/publishedV2/urn:aaid:sc:EU:58639523-5f3f-488c-894e-6d1e5e020702?promoid=Y69SGM5H&mv=other
I am on a Mac using Chrome browser. The files were originally generated in InDesign.
Thanks in advance.