Short answer: it’s irrelevant.
Longer answer: what we are interested in is the delivery of continuous value to our customers. Personally, I have seen teams with 10 developers delivering work of no value and teams with three developers delivering a work of art, satisfying the customer and adding value to the product. And yes, listen to your developers, let them decide what is best for them. As a manager, remove the impediments and concentrate on value and market/user feedback.
PS: The Scrum Guide recommends that a Scrum team should be between 3-9 people. But this is a recommendation, not a rule. Inspect and adapt. For those who refer to a team of four people as a “half team” I raise the following question: China has a population of 1,3 billion. China is a country. USA has a population of 320 million. Four times smaller. So USA is not a country?