nbn Modem Performance - ZTE H1600 or TP-Link VX420-G2H

Hi community

Not sure which NBN modem to get, but I want to upgrade my old TP-Link Archer VR1600v.
Side note: I am currently using a separate AP which could also do with an upgrade, Wi-Fi 6 looks good.

Both of options are supplied by the ISP

• ZTE H1600 ($130 posted)
• TP-Link VX420-G2H (~$150 posted from memory)

The ZTE H1600 seems to be unlocked and can be used with any provider including using the VoIP (so no need for separate ATA device).
I am not sure if the VX420-G2H is locked to the provider (iiNet / TPG), especially the VoIP feature.

Does anyone have any experience with either of these modems, what is the performance or any there any drawbacks?

Other modem suggestions are welcome, needs to support VoIP, WiFI 6 would be nice to have.

Thanks :)