To download, your appstore usually needs to be Thailand version. For Android i use my Thailand registered gmail address, maybe similar for Apple,i then switch between UK and Thailand playstore as required. No idea how good Dolphin is, no ones mentioned it before
I'm in Pattaya and i see Thais paying using their phone for street food, maybe 50%, but they always take cash. Maybe Bangkok is different but i doubt they'd turn down cash
if the passbook showed consolidated items i.e. potentially hiding going below 800k\400k presumably they will ask for statements, that's why it's important to update regularly
Presumably you are eating a lot of fatty junk, drastically cut down on that, sugar\carbs isn't the enemy on their own, only when combined with fatty junk, cakes, chips, pastries, ice cream, chocolate etc
I like this one, next to Pitini, still on Buakhao, tomboy 120+ baht
https://www.google.com/maps/@12.9327106,100.887106,3a,75y,205.95h,90.11t/data=!3m4!1e1!3m2!1sReBoiUBVH552vBYO8_IGXA!2e0
ah right, I'm more round the corner opposite Krungsri\rcon. Hidden away with blue sun shade
https://www.google.com/maps/@12.9328848,100.8871747,3a,75y/data=!3m4!1e1!3m2!1sLr4tkywhbVgalUfmRAGO3g!2e0