The ZyXEL Armor Z2/ NBG6817 would meet the same requirements (and performance limitations) as the r7800, as does the Netgear xr500.
OpenWrt has a factory image for the nbg6817, which can be directly flashed from the OEM firmware - no preparations or special considerations needed. The hardware is effectively the same as for the r7800 (minus the eSATA port); dual-firmware and a reliable push-button tftp based recovery mechanism.
The xr500 is basically the same device as the r7800, just a fancier case and twice the amount of flash, install procedures and performance are identical.
All of these ipq8065 devices are no longer in production and have some performance challenges, but they've been rather common and may be available on the local second hand markets for reasonable prices. They are still pretty decent devices and were among the high-end options for 802.11ac/ wave2, respectively wifi 5. OpenWrt support and stability is good and mature and pretty much equivalent between them. So this is mostly a question of local availability and pricing.