firebase – Server side locks in Cloud Firestore

I am curious about the behavior of locks made during server-side transactions on Cloud Firestore, as shown in this video: https://www.youtube.com/watch?time_continue=750&v=dOVSr0OsAoU

My transaction will consist of reading several documents and locking them. My question is: do these locks limit all access to documents, including simultaneous reads from client code that are not part of a transaction? Or do they only restrict the scriptures?

If they limit readings, is there a way around this problem – this could result in a significant slowdown in the application I'm working on.

Similarly, in the event that a transaction tries to lock already locked documents (what is the re-attempt scheme), how often is this attempted and is there an exponential return?

Thank you!