Wifi 6 is not so much about more devices connecting at a time. It is about the capacity of data to those devices as it allows devices to communicate with the wireless access point by being able to send & receive data packets simulatainiously to more than one device.
In a traditional wifi environment there are only four spacial streams but only one downlink connection so when a device/s is currently engaged in sending data packets to the wifi router & then another device tries to send a packet at the same time it will cause a collision, that device is then sent a "holdoff" timer before it can retry to allow the other to complete. If it is still busy the holdoff time will double, then double again & again. You can begin to see how this would cause the wifi experience for some to appear to slow down. Especially when people are streaming, gaming, watching kitten videos or what ever they do on the internet.
With wifi 5 there are 8 spacial streams & it uses a technology called MU-MIMO (Multi-User Multi-Input Multi-Output) & this has 4 downlink connections. Think of it like four lorrys, each one is carrying the load of one customer & four lorrys can be received at a time.
Wifi 6 uses OFDMA (Orthogonal frequency-division Multiple-Access), this boosts the capacity by splitting the channel into several subcarriers which allows parralel streams. So more clients (as many as 30) can share the same channel without having to wait. This is now like each lorry is now carrying multiple customers loads at the same time while also increasing the number of lorrys that can bve received at the same time.
There are some quite complicated equations but it basically boils down to a theoritical single stream data rate of 600Mb/s in Wifi-6 compared to the theoretical 433Mb/s single stream data rate in Wifi-5.
Wifi-6 also has better penetration & range through obsticles like walls so you will not only benefit from fast speeds but better coverage in your house, especially if you have an older house with thick walls.
So in short you will definately benefit from increased wifi performance even with your hub in modem mode but, your uplink will be the bottleneck as all connected devices will be trunked through the 1Gbps link to the hub. Having said that, it also depends on your internet connection speed. If you have 200Mbp/s for example there is another bottleneck there, although the likely hood of you consuming this is very unlikely. Only 6Mbp/s is require for a HD video stream so you can figure it out, even with many devices on your network all streaming, with a 1Gbp/s uplink & 200Mbp/s internet connection your still going to be flying but you'll have more reliable Wifi.
