My take…No doubt your room is very important. Percentages are just a rough guide that may or may apply very differently to audio junkies. They are most applicable to dedicated room treatments or construction and may very minimally apply to living areas. Sooo many factors are involved that sku the percentages. In my living area working off a corner, valted ceiling, open access, built-ins, furnishings…very little can and needs to be done and it works out pretty well. Tried temp panels and drapery fabric with no improvement and ended up just using a bass trap in the corner behind my system.
Yikes… I know when shopping for home furnishings with my wife the stereo system does and will never take priority or even be considered or discussed. i am enjoying my happy relationship and her tolerance as it is now 🤣.