As long as the performance is OK, 98 RON should be fine.
This is all the the owners Manual says:
Your vehicle is designed to meet all emission regulations and provide excellent fuel economy when using high quality regular unleaded gasoline with an octane rating of 87. The use of premium gasoline is not recommended. The use of premium gasoline will provide no benefit over high quality regular gasolines, and in some circumstances, may result in poorer performance.
It doesn't say that it's harmful, only that it won't provide any benefits. In this case it benefits by being less of a pollutant.