Joining Projects team as an A0 at a T1 firm, what should I expect in terms of work, future scope, transferability between firms, growth prospects, etc.?

Also, any recommendations on how to prepare for it beforehand (I’ve not interned with a Projects team before).

Any help is appreciated, thanks.

For preparation, go through Graham Vinter's book. There are also a couple of country overviews for India available online on websites like ICLG etc., written by people from KCO and AZB. That will be more than enough prep. Having some knowledge about contract review and bankability may also help.