How do you manage user feedback?

Let's start collecting them as soon as you have a playable build.
Feedback are very important.
If the assets are not final, or the overall visual quality is not good enough, run an internal play test, with people who can make the difference between a core gameplay and a final game.

Once you can afford it, probably after the milestone set to deliver a first playable build, make it in a shape to be testable by external people.

Let them play and Watch them play.
Never intervene (inside or outside the game) to explain the mechanics.
If they don't understand them it means your game does not speak by itself (something you should fix).
If you do a play test you can, at the end of the game, let players answer a form.

Test what they have noticed or not. And everything relevant to you and your game.

Read also The first players of your new game should be the players of your previous game.

p.s. you can also share two different versions. In this way you can do the A/B testing (also known as split testing or bucket testing)
It is a method of comparing two versions of a game against each other to determine which one performs better. AB testing is essentially an experiment where two or more variants of a room are shown to users at random, and statistical analysis is used to determine which variation performs better for a given conversion goal.