Reviews are not mandatory on Etsy, so you won't get them for all of your sales.
Most people shop Etsy once and don't return to leave a review. It is of no importance to them. Some will send you an e-mail or Etsy convo instead, because they cannot be bothered to study Etsy's review system.
You want to remember that no news is good news.
Should the buyer have a complaint, you will definately hear from them!
You don't want to beg for reviews either. Most customers will find that annoying. Also, when a customer has no complaints, but you sort of 'force them' to write a review, you might be unpleasantly surprised, because they will go looking for pro's and con's of the transaction and come up with little negative facts, which they never even thought of in the first place. Again: no news is good news.
Another reason why some people (who DO know about the review system) don't leave reviews is because their username will be clearly visible.
In the past, after years of being asked for this, Etsy hid buyers info. Somehow with the new review system they thought it was a good idea to make the info public again. Not all buyers agree with that.
If you still feel the need to ask for reviews, then at least call them reviews instead of feedback, so customers know where to find them on Etsy.
The answers to your other questions about reviews can easily be found on Etsy:
https://www.etsy.com/help/article/102