3) I checked your products and see that you set sale price and regular price is lower than sale price https://prnt.sc/1ur4gn0 It causes issue with the Stock status filter. So, edit your products and remove the wrong sale price.
I checked the price filter option and don’t see the problem with that.
Go to Plugins > enable WooCommerce Infinite Scroll and Ajax Pagination plugin if you want to enable Infinite scroll. We have disabled that for testing purposes.
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