About different personalities of bridge. Interface stats are about bridge interface, which is not on the way between bridge ports (either wired or wireless, doesn’t matter).
Regarding throughput results: the UDP test shows that wireless was able to transfer data at around 900Mbps (one has to observe the receiver side stats). It’s TCP that struggles. And TCP has its own quirks, and when wireless is involved (can be broadband, e.g. 4G, as well), it’s delay jitter which kills its performance. You might get much better overall performance figures if running iperf3 with multiple parallel streams (“-P 8” or something).
Sad thing, which most wireless zealots fail to acknowledge, is that wireless, even if technically it provides high throughput, will never be as good as wired (when promising same throughput) due to systematically longer delay, larger delay jitter and susceptibility to external interference. Add also duplex delay/issues if Rx and Tx use same frequency channel (which is the case with WiFi).
Wireless will never be as good as wires.