ProtonVPN+Japan server(free account gives access to Japan). It works on mobile and iPad too so you can also play on them. I use VPN for just login and then I turn off once I have opened the match game screen, then I just use the normal match feature without VPN. You just need the VPN to login and not for playing it in my experience.
You need to use a 3rd party XML/code editor app. try this app: https://play.google.com/store/apps/details?id=com.rhmsoft.edit
Find the .xml file using this QuickEdit app instead of your phone's file explorer