There is also an alternative option
Which is to downgrade to 100Mbps (with a penalty of contract reset)

That's what I'm going for

As other mentioned, both are crap

The D-Link is known as the "trashcan" and that tplink model is known to overheat

Private
Its within the reserved range for CGNAT
100.64.x.x until 100.127.x.x

The problem is that most apps just send everything through a single "General" channel
cough, looking at you, TnG ewallet

All I will comment regarding the differences between Cloudflare and Google DNS is ECS

https://en.wikipedia.org/wiki/EDNS_Client_Subnet

Cloudflare does not support it, while Google DNS does

DFS Channels, reserved for radar but shared with wifi as well

If its on first boot/change, it might be waiting a few minutes to check the conditions before begining broadcasting
if it's been a while, maybe it detected interfereance and auto changed to other channels

Personally I prefer to avoid those channels whenever possible