Slow External Access, Trouble With DuckDNS / Let's Encrypt

Hoping someone can point me in the right direction here.

Running Home Assistant in a Virtualbox VM, network adapter is bridged. Host is Linux Mint 21.2
If I port forward 8123:8123 at my router and try to access home assistant externally using my IP address it “works” but load times are upwards of a minute per page.

I also wanted to use DuckDNS and Lets Encrypt instead of my external IP. I have the duck DNS add-on installed and configured, but cannot seem to get the Lets Encrypt addon working. I believe this is because it needs port 80 forwarded? Unfortunately my ISP (Telus) does not allow incoming traffic on ports 80 or 443. I was going to access using https://mysub.duckdns:8123 to work around this, but if I cannot get Let’s Encrypt setup without being able to allow incoming traffic on port 80, perhaps it just isn’t viable.

However, even using the DuckDNS url to access externally results in ridiculously long load times. Machine is connected directly to the router with Cat6 on a 1Gbps port, internet connection speed is gigabit up and down.

Using Nabu Casa / Home Assistant cloud load times are perfectly fine.

Why would you need to allow inbound 80 for let’s encrypt?

Sorry, I saw that as a requirement on some old documentation. I guess it is no longer needed.

Here is the error I am getting in the DuckDNS logs:
INFO: Renew certificate for domains: and aliases:

INFO: Using main config file /data/workdir/config