Took me about 3 full days to implement this using cert-manager and ingress-gce. Very technical and fun project to work on and very satisfying when it worked for the first time.
Previously I sold this feature to the enterprise plan and did the setup manually, now when the software do all the work I decided to move the feature down a price-plan. I think this feature is expected to be included in paid plans nowadays.
Lessons learned: When you get stuck on something, a workout and some fresh air can really help you get past.