Oil Change Company Additional Recommendations (2019 Sport)

I use an oil change place like a lot of you guys. As we all experience most of these places try to sell you additional services.

On this latest trip (70,000) they suggested a transfer case flush and a radiator flush.

I always here a lot about Subaru and CVT and transmission, and figured an oil change place isn't the right place to screw around with my transfer case.

Is this something that should be done? Should it only be done by dealer? I also have a mechanic who does my brakes and plugs and such and trust more than the oil change place.

Same for radiator flush. Is that something I need to do on a normal basis. He said I need to do it before winter really hits (I am in New England).

Thanks for any advice and info.