@AIpatii 

Hi,

There hasn't been a definite statement from TP-Link whether support for extending the IoT network will be implemented in the future.

But note that if you update both AX55 V1 to firmware version 1.3.5 you should be able to extend the Guest network, if that is of any help to you.

https://community.tp-link.com/en/home/forum/topic/786342

Regarding the connection speed (link speed). I have noticed it as well that when I mesh my AX55 V1 and AX53 V1 together, then the satellite router runs at a channel width of only 80 MHz for the most time, which results in a link speed of 1200 Mbps, while at the same time the main router broadcasts with a channel width of 160 MHz (= 2400 Mbps link speed). 
Since the channel width is being adjusted by the router automatically there is nothing the user can do about it.