Relaxed validation for numeric format filters

Continued from f96bff99cb

Closes #6782

yt_dlp/YoutubeDL.py

@@ -1932,7 +1932,7 @@ class YoutubeDL:
             '!=': operator.ne,
         }
         operator_rex = re.compile(r'''(?x)\s*
-            (?P<key>width|height|tbr|abr|vbr|asr|filesize|filesize_approx|fps)\s*
+            (?P<key>[\w.-]+)\s*
             (?P<op>%s)(?P<none_inclusive>\s*\?)?\s*
             (?P<value>[0-9.]+(?:[kKmMgGtTpPeEzZyY]i?[Bb]?)?)\s*
             ''' % '|'.join(map(re.escape, OPERATORS.keys())))