Im trying to say that third party success on nintendo machines is always mediocre compared to succes of third party games on other consoles. Its really hard to be even as half as succesfull as nintendo is on their own platforms.
The success of third parties in Japan is actually competitive on Switch vs PS4. Some games do less than PS4, others more, some even. My Hero One's Justice for example did better on Switch. Dragon Quest Builders 2 is pretty even. And so on.
One issue though is Switch gets some of these games late and that does impact sales. Also, some of these series have spent years ignoring Nintendo platforms entirely. It will take time to build an audience on Nintendo systems just as it took time to build one on Sony systems.
The problem isn't third parties not selling as they normally do, it's Nintendo happening to control 5 or 6 of the most powerful IPs in Japan