Maybe the opposite will work.
Remove a section near the top and apply rooting hormone to it. Then plant it. Can't say for sure.

Maybe find a landscaper who will trade for a shorter one.

A cut Cyathea cooperi is a dead Australian Tree Fern, they don't reroot or resprout. Some of the Dicksonia species can be rerooted from dug up trunks, but even these are a bit tricky for the average gardener.

Yes you can cut a Cyathea cooperii off if it gets too tall. Keep the top plus enough of the top trunk to replant at the height you want plus half a metre to be buried in soil. . The bottom part will not regenerate and needs to be removed. Trim back the old fronds being carefull not to damage the new unfurling ones. Replant in fresh slightly acid soil, give it some organic fertilizer, water the trunk and base well but not the fronds. Make sure there is adequate drainage. give the plant some dappled shade if you can.