is AX router needed for 1Gigabit PureFibre ?

If you really need the full bandwidth, hardwiring with ethernet is always the way to get it if on gigabit. I get consistent 940/940mbps that way.

You are likely confusing the theoretical max available bandwidth of a wireless NIC or the router vs. the actual speed you get to an individual device. The latter is always lower. While you may have an  802.11ax NIC, you won't see 866mbps ever when using it. Many wireless routers, even some brand new expensive Wifi6 mesh routers have a max speed per device of about 500mbps. It's just the way the wifi protocol works.

Wireless speed is also never guaranteed as there are so many environmental factors that affect speed. You mentioned your place is about 600sqft. If you are in a condo or apartment, you'll also have a lot of other networks nearby and that will also impact the wifi speed.

I am in a condo and I can see give or take about 50 other wifi networks in range. Even with that, when using my T3200M wifi, I get average about 500mbps down / 400mbps up over 802.11ac 5GHz wifi. That's pretty typical for most Wifi5 routers. If I connect to the Wifi6 Boost AP from Telus, which is 802.11AX (if you have it configured right), I get about 665 mbps down / 465 mbps up. Both of these speeds are while I'm within about 15ft of the Boost AP which is on the other side of the wall from me.

If you had a dedicated wifi6 AP, you may get faster speeds but you likely wouldn't notice any difference between the T3200 and Wifi6 for every day use. If you're downloading huge files like games, then yes there will be a more notable difference of maybe a few minutes. If gaming, ethernet is always better anyways. If you like the simplicity of having one device, keep things as they are now. The currently offered equipment from Telus would need the separate Boost wifi AP for wifi as the NAH has no wireless capabilities of its own.