Taints are not supported in Syself Autopilot. This is a limitation from Cluster API.
Taints must be applied directly to the Node object inside your workload clusters. However, CAPI can only interact with objects in the management cluster, meaning it cannot add a taint to an existing node.
Even though it is possible to manually taint your nodes using the kubectl taint or edit commands, you shouldn't rely on this method. It is not persistent and the taint will be gone if the node gets reprovisioned or your upgrade the cluster.
The same effect can be achieved by assigning labels to the nodes and using node selectors and affinity rules to influence the scheduler and make pods go to specific nodes.