Hi Mliebe74 and welcome to the site.
Since this is a new bike I would stay with factory settings for the time being.
I assume it runs ok once it is warmed up, is that the case.
I would review want others in the 150R section of the site have done regards jetting for future changes. It obviously depends on your elevation and ambient temperature of where your son is going to ride.
https://www.crfsonly.com/forum/viewtopi ... 67&t=13471
Most are older models so might be some carb changes to the 2022.
Hope that helps
What I would do is in consultation with the owners manual adjust the rear sag on rear suspension as this will make it easier to ride.
Following the set up will let you determine if a spring change maybe required.