A few tips for Wi-Fi bandwidth optimization.
If you set up multiple access points/routers, it's important that they be set to different channels. In 5 GHz, with the usual 80 MHz bandwidth setting, four channels will be used. The channel you set in the AP UI is the control channel, where all management traffic is. When data is sent, the four adjacent channels will be used.
So set one AP to a channel in the low (36-48) band and one in the high band (149-161).
The exception to this is if the APs are far apart enough that they don't detect the other's traffic. Then you can re-use channels.
The other important thing is your devices. Both Wi-Fi 5 (11ac) and Wi-Fi 6 (11ax) APs/routers are much better than Wi-Fi 4 (11n) at not letting slower devices eat up bandwidth. That said, devices farther away from an AP, no matter what Wi-Fi type they are, will use more airtime (bandwidth) than devices closer to the AP. Also, if you DO have 11n devices, I suggest replacing them with Wi-Fi 5 or 6.
The most bandwidth intensive applications are video conferencing or any other "live" service where content isn't already stored. Content streaming (Netflix, et al) are actually very good at minimizing bandwidth use. Contrary to the term, these services do not continuously "stream". They intermittently download chunks of content that are buffered locally.