From a visitor perspective when he lands on a particular post review which has static items already prepopulated (including the product which post review is about), I am sure it would be very beneficial to also have the option to add more other items to the comparison. As you can't hope visitor will find and use a dynamic comparison page unless you highlight that option across the whole site.
The right side compare icon only appears when you already add something to compare. Maybe if that button with compare icon on the right side of the site would show all the time (it seems it doesn't show on posts if static items shortcode is used and on other parts of sites only if you already add something to comparison). And if it would have an integrated option to search and add products for comparison and not just to see already added products, it would be perfect.
Maybe add an option to show related products below static comparison which you can add to the comparison.
Giving the opportunity to see the pre-selected comparison and add/remove products would be very beneficial to visitors. People don't like to work much, they want information asap.
Also, it seems the comparison icon is not exactly visible on the products archive unless you hover over the image, and it is really small in other places too. Maybe because I use clean Rehub with no special child theme.
These are just ideas. I think the comparison option would become more useful with additional improvements would be added. Hopefully, you will take some into consideration. For now, I will use as it is.