with the VPN speed you've mentioned, the main reason for x86 would be the gigabit speed.
check with the seller of https://www.ebay.co.uk/itm/175594129758
text says CR25wing, photos say CR15ing.
CR25Wing would fit your needs, but it wouldn't come with the kind of wifi (that's what the W
stands for in the model name) you'd like. Obviously the non wifi CR25ing would work too.
spend the rest of the cash on a used router or AP.
there's more info in Cyberoam CR25iNG / CR25WiNG wired router HW discovery and [HOWTO] Installing OpenWrt on Cyberoam CR15(w)iNG and CR25(w)iNG