When was the last time you used Jenkins? I don't get the hate. Not only from you, but lots of people on the internet. What makes Jenkins stand out IMO is the community and the core maintainers, they are perhaps moving slow, but they are moving in the right directions. The interface looks really nice now, they've done a lot of ux improvements lately.
I haven't used Jenkins in a few years, so some of this might change, but in working with it I saw that Jenkins has a few fundamental flaws that I don't see them as working to change:
1. There is no central database to coordinate things. Rather it tries to manage serialization of important bits to/from XML for a lot of things, for a lot of concurrent processes. If you ever think you can manage concurrency better than MySQL/Postgres, you should examine your assumptions.
2. In part because of the dance-of-the-XMLs, when a lot of things are running at the same time Jenkins starts to come to a crawl, so you are limited on the number of worker nodes. At my last company that used Jenkins they instituted rules to keep below 100 worker nodes (and usually less than that) per Jenkins. This lead to fleets of Jenkins servers (and even a Jenkins server to build Jenkins servers as a service), and lots of wasted time for worker nodes.
3. "Everything is a plugin" sounds great, but it winds up with lots of plugins that don't necessarily work with each other, often in subtle ways. In the community this wound up with blessed sets of plugins that most people used, and then you gambled with a few others you felt you needed. Part of this problem is the choice of XMLs-as-database, but it goes farther than that.
4. The way the server/client protocol works is to ship serialized Java processes to the client, which then runs it, and reserializes the process to ship back at the end. This is rather than having something like RPC. This winds up being very fragile (e.g.: communications breaks were a constant problem), makes troubleshooting a pain, and prevents you from doing things like restarting the node in the middle of a job (so you usually have Jenkins work on a Launchpad, and have a separate device-under-test).
Some of these could be worked on, but there seemed to be no desire in the community to make the large changes that would be required. In fact there seemed to be pride in all of these decisions, as if they were bold ideas that somehow made things better.
both the old & new interfaces to Jenkins are riddled with bugs, work seems to be maintenance mode, across the plugin ecosystem too
If you are talking about Jenkins-X, that is a different story, it's basically a rewrite to Kubernetes. I haven't talked to anyone actually using it, if you go k8s, you are far more likely to go argo
