Here in New Zealand, 91 and 95 are at every gas station and a very few have 98. Dad’s car (2000 Nissan Maxima) runs best on 95 (pinks on 91)
How many kilometers does your car have on it? I have seen coils go bad, but usually these are high mileage cars.
Octane ratings given in the United States are not defined in the same way as those in most of the rest of the world - this is likely the reason for the higher numbers seen in the OP’s post, and in New Zealand.
There are two commonly accepted ratings - the Research Octane Number (RON) and the Motor Octane Number (MON) - details here. They are obtained in different ways, and for typical modern automotive fuels produce different numbers: the MON is usually 8-10 points lower than the RON.
In the US, the quoted “octane ratings” for pump fuels is the average of the two: (RON+MON)/2. In most of the rest of the world, the RON by itself is used. So the very same gasoline would have a posted octane rating 4-5 points lower in the US than it would elsewhere in the world - simply due to differing definitions.
Here in the Los Angeles area, the most common (RON+MON)/2 octane ratings seen at gas stations are 87, 89, and 91.
As a matter of fact I just checked today. 265,000 KM, a 2002 model as I said. It was previously used a compound shuttle.