[labawi]

Have you considered bringing an AP closer to the client? Especially on 5GHz a good line-of-sight / line-of-reflection is very helpful, and some extra 10-20dB of signal should compensate for a lot of interference.

OFDM MU-MIMO AX 20000+ 1000$ routers with 20 antennas work better, but in an inconvenient location, when the noise floor is high, it has no chance to compete with a decent 2-antenna ac (or even n) AP with good signal propagation (same room vs. behind a wall somewhere).

And it would be helpful if you can agree with your neighbors to use narrow channels (less competition and unintended interference), decrease radiation power (less distortion => better signal) and if supported, increase minimum bitrate (faster communication => less jamming). Also, lower transmission power and faster SSID broadcasts help induce roaming, for when you have multiple APs.