I have been waiting for this for years now so I am glad to see you finally are doing something about it since woo is such a huge part of WordPress.
First an answer to your last question.
PG WC would finally make it possible to have a full solution without a pagebuilder, and now all projects I have had that involve woo I used Elementor or Oxygen to save time.
It’s simply not time-effective to use pinegrow to make the main template and then hand code the wocommerce part so for each site. If a client needs woo I go for Elementor or Oxygen and just skip pinegrow all together.
Elementor is by far the best when it comes to customization options for woo out of the box but with a bit of manual coding oxygen gets the job done well and performance-wise much better than elementor.
I would not mind a bit of PHP code and things like that as long as you have to option to customize and style everything.
I can’t answer any of your other questions because I do not hand-code woocommerce sites because most of my clients does not care how I do it as long as I get the job done and as fast as possible and in most cases, hand-coding is not an option unless the client has a bigger budget.
What I suggest is to have a look at Elementor and Oxygen and see what they do and try to implement something similar or better.
Oxygens options for woo are a bit limited but a guy on youtube just made an awesome tutorial and how to style and change everything in oxygen with small bits of PHP code ,some custom styling and with a few small plugins such as wishlists.
I suggest you have a look at those tutorials and get some inspiration from them and maybe you can find a better way to handle the problems or if we could do the same in PG WC it would be awesome because then we finally could stop relying on pagebuilders.
Not sure about posting links and things here so ill post his youtube channel and you can just find it yourself on youtube.
His youtube channel is “Design with Cracka” and he got a whole tutorial called how to build a woocommerce store in oxygen and it’s an awesome tutorial and you should get some inspiration on how to do things in PG WC.