In the United States my entire life I have always been able to port forward when necessary, though I've only been on two or maybe three providers. I also would help friends in middle and high school port forward so we could connect to their game servers. Many providers seem to try to make it as hard as possible, attempting to lock down the interface behind a web panel. This can typically be bypassed by finding the real panel address locally or by getting a new router that isn't locked down. Growing up it was extremely easy, my provider didn't try to make it difficult, but now there is often a barrier to entry for people who desire to casually tinker with their network setup, which is unfortunate.

We just switched to Metronet last month (5gbps symmetrical!), and while we have to pay $10/month to get a public static IP (CGNAT otherwise), they didn't care what was connected to the ONT, which operates below the IP layer.