As
Phil has mentioned, xDSL is very much a black art. A modem/router that performs well for one person, under one particular set of circumstances, may be sub-optimal for another person's usage case.
If you can source a ZxYEL device, at a reasonable price, then it would be worth trying. The fact that your circuit connects to a Huawei equipped cabinet is good hint that you
may obtain better performance with a ZyXEL VMGnnnn-B10x device.
I'm looking to replace my Draytek Vigor 130 as it disconnects every few weeks . . .
Exactly what happens when "it disconnects every few weeks"? Is it the VDSL2 (ITU-T G.993.2) link to the Openreach DSLAM that drops? Is it the upper layer PPP session to your ISP/CP that drops? (The former will also cause the latter to occur but the latter will not cause the former to occur!) As you are using a "two box" system, the former can be caused by the modem whereas the latter can be caused by the router.