Regarding this being an XP issue, I can't say for sure. Perhaps it's a browser issue.
using https://www.deviceinfo.me It clearly shows the O/S (True Operating System Core) as well as the user agent string.
Doing a search to have browser spoof the O/S (like the user agent), people say it is impossible short of involved and impractical methods.
I am not convinced. Somewhere there must be a byte line that can change NT 5.1 to e.g. NT 6.3 (Windows 8.1), presumably that does not break the O/S.
Regardless of if this is an XP issue,
I believe it in all our best interest to find how to spoof "True Operating System Core"
Ok So after some digging, I found that one can indeed spoof the O/S and via a not particularly difficult process (This is for Mozilla browsers).
So I spoofed my XP (Windows NT 5.1) O/S to be Windows 8.1 (Windows NT 6.3)
1] Go to https://www.deviceinfo.me to see what your browser is displaying, This line is the key one: True Operating System Core: Windows NT 5.1 (32-bit) (or 64-bit).
2] Back up your prefs.js file (This stores your about:config settings). You should find this here (This is an example your browser may be different):
C:\Documents and Settings\XYZ\Application Data\Moonchild Productions\Pale Moon\Profiles\tn69ivdz.default.
3] Go to about:config and search: general.oscpu.override
If it exists you will edit the value, If it does not exist, create:
right-click context menu: New -> String name: general.oscpu.override Value:
Windows NT 10 (Windows 10)
or
Windows NT 6.3 (Windows 8.1)
or
Windows NT 6.1 (Windows 7)
4] Open a tab and go to https://www.deviceinfo.me to check changes.
To revert the changes,
Go to about:config and search: general.oscpu.override right click and choose reset. Close browser and restart browser, Go to about:config and search: general.oscpu.override if not gone, close browser and overwrite prefs.js with your backup copy you did make a copy right?
Unfortunately this did not change my bitchute video issue.