That is exactly how nuclear outages work. Everything is planned in a resource-loaded schedule and many of those resources are just there for the outage.

Finland is actually somewhat known for running short (1 year) cycles with very very short (<10 days for refuelling is not unheard of) refuelling outages every other cycle alternating with slightly longer maintenance outages. A more typical scenario in the US would be 18 month cycles with a 30ish day outage. Some plants are moving to 24 month cycles with slightly longer outages.

Capacity factor for nuclear plants in the US is consistently around 93% (similar figures in many other countries as well), which is significantly higher than other generation sources.

Most reactor downtime is due to refueling, since that requires cooling down the core through several stages. AFAIK it's not practical to do it safely and economically in under a few weeks.

Most reactor maintenance is already done during refueling so there isn't much more room to optimize that downtime. (though that may change the older a reactor gets)

Most reactor downtime is actually for maintenance during refueling windows. As I mentioned in another comment, there is experience doing refuelling-only outages in <10 days. If everything goes well, you can startup a PWR from cold shutdown to hot full power in 3 12 hour shifts

Rushing maintenance costs more, and nuke operating cost is already radically more than renewables + storage.