Is Traefik difficult to initially configure? I use the default ingress-nginx controller on my home lab setup (separate from the “official”, non default & non-free nginx-ingress, absolutely terrible name choices) and it seems to be ok for smaller use cases. It’s not without its idiosyncrasies though.
At previous employment with large scale clusters (thousands of nodes) Traefik seemed to be heavily preferred by the SRE’s in my org.
I personally think it's not that bad -- the documentation is a bit overwhelming because there are so many ways to configure it (some people are running with only docker, others using the CRDs, some people are using the built-in Ingress support, some using the new Gateway stuff). As with most things, if you read and mostly digest the documentation, you won't feel lost when it comes to setting it up -- I haven't run into any corners that were too hard to figure out or inconsistent (which is even worse).
You could get Traefik working inside your existing cluster actually by just letting NGINX route to it and seeing how easy it is to use that way -- though that may be more difficult than just spinning up a cluster on a brand new machine (or locally) and feeling your way around.
I can say that Traefik's dashboard makes it much easier to debug while it's running as it gives you a fantastic amount of feedback, Prometheus built in, etc.
At previous employment with large scale clusters (thousands of nodes) Traefik seemed to be heavily preferred by the SRE’s in my org.