Disclaimer: I know its a first world problem but WTH do you expect from me.

As of yesterday I have 3 wired internet connections, they all suck in different ways.

Cable Connection: 1.25Gb down, feels like 0 up. Randomly disconnects multiple times throughout the day for a few seconds at a time.
Fiber 1: 1Gb symmetrical, crap IPV6, some backend routes are congested as hell and any lightning fries the OTN.
Fiber 2: 2Gb symmetrical, no IPV6 at all, so many levels of Nat I can't even count them.

After a number of emails and (ugh) phone calls I managed to get a real public (probably dynamic, but whatever) IPv4 address and a bridge mode device. No native IPv6 but HE tunnel seems to be working reasonably OK.
@paul ouch. Here in the UK I managed to find an ISP that just activates the ONT in the house, allowing me to use whatever firewall and router I want (UniFi in my case) as well as a static IPv4 and a static /56 IPv6 PD. Dual-stacked on all 5 VLANs now; will go IPv6-only on my trusted LAN whenever UniFi step up their IPv6 game and provide a built-in NAT64 gateway. It's 900Mb down and 100Mb up, and feels very consistent.