Okay, then to answer your questions,

1. No
2. Not really. Syldra parts take a LOT of materials for barely any bonus stats.

Most people are only upgrading Unkiu, and Colecanth parts. I know of one build that is using a Shark bow as well.

So you will either want to re-think your builds entirely if you want to farm the new zones for rares, or use them to farm the new materials or old zones while you wait until they add lv. 60 parts to the game. We have no idea when they will add lv. 60 parts but since they increased the level cap they will probably add them at some point during the expansion.