Any recommendation better than C7 but not as good as R7800?

In general, look for mt7621 (Xiaomi mir3g, ZBT WE1326, ZBT WG3526, AFoundry EW1200, ...), ipq40xx (AVM Fritz!Box 4040, ...) or entry level mvebu (Linksys WRT1200AC); if you're looking for r7800 like performance, the ZyXEL NBG6817 is almost identical (more flash (4 GB eMMC), but no SATA), but can often be found a little cheaper than the r7800.

Check the individual device pages before buying, for mt7621 I've only listed popular mt7603e+mt7612e devices, for ipq40xx I've only listed devices with more than 128 MB RAM (ath10k needs RAM) and at least 16 MB flash.