Hello Jesus
first IPX is a very old novell protokoll an had nothing to do with IP or TCP or UDP or anthing else…
Normaly there must a vergood reason to use it.
I thing 32 Bit windows can use IPX client … A nice support you find withn XP, later it will complicated.
http://www.solemnwarning.net/ipxwrapper/
Normaly you need a direct contakt between the NICS. Than IPX will be transported.
VPN / OpenVPN there are 2 types of contacts tap and tun. Tunnel is tun and a IP Connect that cant working. With Tap you had a chance. Normaly tap let fly the complete (mostly) Ethernet packages across the VPN. Tun uses only the smaller UIP packages.
I didnt know how long the latency is over VPN. That can be a problem. Try it first with a TAP VPN in your local Network before using the Internet …
and a serach like IPX over VPN can be helpfull
https://radmin-club.com/other-games/how-to-play-ipx-games-over-the-internet-using-radmin-vpn/
Thats all i know know …