Platform engineering is the discipline of designing and building toolchains and workflows that enable self-service capabilities for software engineering organizations in the cloud-native era.

Platform Engineering

I have used it in 2018-2022, and the experience was pretty good. There were few bugs back then w.r.t. permissions and race-conditions, but believe it to be more mature since then.

One of the thing to watch out would be fast release cycle and making sure you are up-to-date, given the releases were a bit bug prone back then (being v0.X releases).

Do you know perhaps is it possible to use KafkaConnector CRDs, but instead of running the connect jobs it in a self-managed KafkaConnect cluster (managed by Strimzi), run it in the Confluent Kafka Connect cluster?

No, I am not aware about it and the knowledge can be outdated.
The community and maintainers were quite active in their slack, you can probably check there once.

If you are searching for simplicity take a look also to redpanda