What was wrong with WinXP 64-bit? I don't recall any compat issues running that back in the 00s, at least beyond what was normal for 9x/NT era software running on 2K/XP.
Let's clarify one thing, there were two 64-bit releases of Windows XP:
Windows XP 64-bit Edition. This runs specifically on Itanium only and was wholly impractical due to steep performance overheads emulating x86.
Windows XP Professional x64 Edition. This runs on x86-64 and is the direct predecessor to the 64-bit releases of subsequent Windows versions including the latest which is Windows 11. This was impractical due to a lack of drivers, it was essentially too advanced for its time.
In my parent comment I am specifically referring to the former.
