Well we don't have working fusion reactor topology yet but the current "reactor" components are low level waste so safe within 40-100 years. Which is still a hell of a long time. Also they still will require biological shielding and associated materials are quite difficult to deal with (concrete etc).

I expect that the longevity of their attention is considerably less than this, particularly if the LLM boom crashes. ROI will not pay for the disposal later down the line.

The claims of low level waste from fusion reactors implicitly assume that impurity elements (like, say, niobium) that would produce long lived activation products can be reduced to very low levels. This may drive up the cost of materials dramatically.