Working with a bunch of newsletters helped me realize one of the best pre-launch practices is creating a test group.
It doesn't have to be big. Just a small group of 30 people who you trust to give unfiltered feedback + are the ideal audience for the newsletter you're building.
This practice is easier for creator-led collaborations/businesses because their distribution allows them to access people quickly. Even without creators, I recommend creating a small test group.
Create 2-3 sample issues and ask what the test group feels about the newsletter.
Forms or polls are popular for collecting feedback, but I prefer one-on-one conversations on chat/voice notes/calls to understand nuances better.
Once I spoke to 63 people on a single day in DMs. Twitter is fun this way. The conversations brought 38 subscribers and deeply valuable insights.
I am sure a Google form won't get the same results.
Moral? Your newsletter will undergo immense iterations and refining before its first issue. Plus, you will have some early subscribers. Bonus.