@EPerezF, WiFi is a half-duplex shared medium. Half-duplex means high latency due to change of directions when transferring data, shared means even higher latency when not enough AirTime is available, e.g. due to interferences of nearby APs in your neighborship.

Nothing unusual so far.

If your goal is to get best latency, clean up the wireless environment. Connect every stationary device (smart TV) by cable, not wirelessly. Use 20 MHz channel width even for 5 GHz, fixed channels, do a survey to find best channels. Throughput will be ¼ of max. theoretical thorughput.

If your goal is to get best throughput, use 80 MHz channel width for 5 GHz, ac-only mode if possible, fixed, non-overlapping channels (you need 16 (!) 5 GHz channels at once for 80 MHz). Latency will be high when available AirTime is low for whatever reason.

Maybe WiFi-6 will give a better latency, but it will need years until all client devices fully support WiFi-6. And I guess WiFi-6 APs will be much more expensive than WiFi-5 APs.

If you want a guaranteed latency < 1ms over the air, you need to use other (proprietary) techniques beyond 802.11 WiFi with at least two simultaneous wireless links, one for sending, one for receiving data, thus implementing a full-duplex transmission. Such devices exist, but they are very expensive.