Welcome, for safety...
There is known vulnerabilities and been proven hacker can override own firmware and turn as zombie/bot net, I suggest not using this D-Link, perhaps use stock ONU

It can be bridged, so double NAT can be avoided

problem is there seems to be serious speed issues, a lot of people have it drop to 300Mbps randomly and only a reboot resolves it

Well, 1gig Lan port = 940Mbps in the real world
2.5gig Lan port can help you extract that last 60Mbps or so for a true 1gig

But yes, the bottleneck will mostly be in international routing

Own ONU/ONT, not supposed to replace on your own, but the TS of this thread sells their own customized one

all own devices, many big company I setup use my GPON stick, as they don't want ISP and Gov spying and/or take control, especially at ONU.

Who knows, now DNS has been hijacked as per MCMC requirement.

Future? all using ONR, ISP can override bridge mode into router mode and prevent user using own Router...
Or SNI intercepted (force using TLS1.2 and detect Domain Name in HTTPS header)
Or even worst ONR do the MITM attack.

Even you disable TR069, ISP can manage your ONU/ONR from OLT.

this what GPON Stick come... Ignore, Override and Reply fake OK to OLT and keep bridge mode.

ISP can say giving ONR is able to reduce cost, but I don't believe it!

Like Huawei EG8010Hv6 is just dumb one LAN port bridge that Allo in Penang using it.

But... One LAN port no longer allow customers use two ISP
TM no longer allow to subscribe multiple ISP for quite some time, EG8010Hv6 + AX3000/6000 router still cost effective and as usual user can use own router,

TM so big, can ask Huawei to make EG8010Hv6 with POTS variant for analogue telephone, and still cheap.

If you want avoid tampering by big boyz, don't use ONR, if you have old ONU, use it, or buy used Huawei ONU like HG8240H, HG8240H5