So, I am working really hard on editing book 1 right now to a story idea. And I made sure to stay in just 1 POV the entire book. Which was reasonable because book 1 was about a main girl finding a team. So it was very much her assembling them while not dying. But book 2 was gonna explore there relationships more closely and I realized that for some of these ideas to work. They can't all be there and I can't have that main girl always there. Basically it's a five man band which benefits from different chunks of them working in groups So shifting the pov between them as needed seems better But I am worried I might alienate a reader who preferred just one POV. Thoughts?
I wouldn't sweat it. Anything you do will alienate readers. And if enough people buy the first book to make pissing somebody off a possibility, well, that's a good problem.
Changing POVs isn't as bad as you seem to think. It needs to be done at scene or chapter breaks though. Depending on your story. You might write the same scene again from a different pov, highlighting the differences in each characters world view.
If you do it well, you can do anything. I don't know of many books that switch POVs in the following books of the series, but one really good example I can think of is Harry Potter. Super popular series, and all of the sudden in book 6 the first chapter doesn't even have Harry. It's 3rd person from the perspective of the muggle prime minister. It's only one chapter in that book, but it works really well and is probably my favorite chapter in the series. So you can totally introduce new perspectives later on in your series if you want to. As long as there is a purpose to it I think you can make it work.
For authors changing POVs effectively take a look at Harry Turtledove. How few remain The Great war series American Empire series And Settling accounts series All follow multiple PO V characters, with their own story arcs, and their stories all weave together to show broader events, from a wide verity of POVs.