I have VSCode set to use CP437 as my codepage and show control characters for "plain text" files, which works surprisingly well as it's only older art/projects/bbs stuff, generally anything else is a specific file type that will use utf8 by default.

    "files.associations": {
      "*.msg": "plaintext",
      "*.ans": "plaintext",
      "*.asc": "plaintext",
      "*.rip": "plaintext",
      "*.nfo": "plaintext",
      ...
    },
    ...
    "[plaintext]": {
      "files.encoding": "cp437",
      "files.eol": "\r\n",
      "editor.renderControlCharacters": true
    },