I realize this product is meant to protect exterior surfaces from reflection, but I my questions are actually about it's performance from within the interior. We get blinding sunlight through our kitc

This particular film is designed to stop intense heat and melting of siding and turf etc. If you are only having the interior issues, then I would use either the Ultra Glare or UltraCool series films shown below. https://www.decorativefilm.com/product-search?Search=ultraglare https://www.decorativefilm.com/ultra-ultrablock-heat-blocking-films