Still using Termux + nvim for most things, including viewing and formating json. If you find an GUI alternative that can actually handle big files let me know.

it's quite pathetic. i load it in gedit and it takes an eternity to render. i open it in my jetbrains IDE, and it displays immediately and warns me it's a yuge file, so it's read only.

virtually all json viewers and text editors can't cope with much more than about 64Mb files, because they are gay and lame