They definitely do both. I haven't checked this years releases, but this is what I found searching my posting history for my physical copies last year:Those are two PHBs and the Planescape adventure. The PHBs are several years old and the Planescape book came right out of a box of em sent by WotC and not via any retail channel.
They do and will print in China.
I believe they prefer not to.
- Call of the Netherdeep: Printed in the USA.
- Monsters of the Multiverse: Printed in China.
- Radiant Citadel: Printed in the USA.
- Shadow of the Dragon Queen: Printed in China.