Need for A Mobile Device App

I know this has been mooted before but with many groups returning to in person games, the lack of a mobile app with local storage is really starting to hit home.
I love Demiplane and its style, use it a lot for reference but when I’m playing away from my house, trying to use the browser version isn’t much good, especially in areas where wifi or 5G aren’t available.
A games shop has just opened up the road and has tables we can use to play on, but it’s in a bit of a dead spot for phone coverage, it’s pushing me to move to the pocket edition physical books as they’re more portable and reliable.
(wish I could put the shop’s name here and get them some more publicity, they’re trying to get the gaming community working with them to get things right from the start)

I don’t think this has to be a mobile app. We do need an offline solution as I’ve also had similar issues. I keep all the pdfs local, but it’s not ideal