Am I sharing my IP address/ location with my host instance?

You share your IP Address with ANY online service you interact with. This is how it talks back to you to send you content.

is there a log of my view history

Not by default. However, enabling verbose logging on the webserver can indeed log this information. Just- not in a pretty way.

are there general privacy concerns that I am not thinking of?

Anytime you comment, post, or vote, that data is stored in a database and sent to every other instance subscribed to the community for which you are interacting with, and then stored in their database as well.

So- tldr; lemmy isn't really a privacy-focused place. Although, its honestly not much different then reddit. Reddit logs EVERYTHING you do, and then shares that data with third parties for the purpose of advertising.

Although, there isn't anything in place in lemmy to prevent this data from doing the same thing. Silently, and without you knowing.