Just keep in mind, that the CPUs of the HH5A or the TP-Links was designed when ADSL with its theoretical top speed of ~23/3.5 Mbps was considered fast, so do not expect wonders...
Case in point on a 116/37 (nominallt 100/40) VDSL2 link I use an HH5A with OpenWrt configured as bridged-modem and connected to my primary OpenWrt router, since only running VDSL2 at ~110/37 with the bridging already maxes out the CPU, so there is, at least at that speed, no reserves for potentially required things like, PPPoE/firewall/NAT/WiFi processing/... (let alone CPU hungry uses like traffic shaping).
And the synchronization with the DSLAM is not great with Lantiq chips compared to Broadcom chips...
in the past i used some rooted Technicolors DGA4130 and DGA4132 from the italian TIM ISP, in VDSL mode, the sync was execellent with the BroadCom 63138, but unfortunately it was not possible to install openwrt on it, we were stuck on the oem openwrt based version.
Mwah, with the latest Vectoring changes, my (lantiq xrx200) HH5A@OpenWrt is now as robust and reliable as the broadcom based (bridged) zyxel modem I used before; both also end up with exactly the same DLM-constrained sync profiles. That was different in the past, before @janh's patches, when the broadcom was much better. I guess broadcoms CPE might still perform better with broadcom linecards on more marginal lines.