Anyone having experience in running kaniko in a flyte workflow? Would that be done with e.g. a ShellTask?

I think that’s correct — though, is there a way your workflow could return the URL(s) of artifacts you care about? We do something like this where we use Flyte to build some artifacts (ie train a model) and then fetch the artifacts during the container build step (we have both steps as stages in a GitHub Actions workflow)