Anything can happen over 7-8 years or longer. Chega might win majority over this time frame. PS might pull the rug when it’s time to apply for citizenship. Europeans might start drafting your male offspring. Who knows.
If you must have a plan B asap and have serious money, then look up what Peter Thiel did (Malta and NZ).
If you are five years from retirement and LOVE Europe, skip GV and just start spending longer holidays in Europe, to make up your mind where the retirement house will be—then do passive income visa when you are ready to move per my old post.
If you don’t have Peter Thiel type of money, but have enough to not feel anxious about 500k Euro (ok with investment losing $$, ok with not getting a residency card for 3-4 years, ok with mild abuse from bureaucrats, ok with the currently small risk of not receiving a passport after 7 years of 7 days per year—again, the risk might become big, ok with the significant risk of having to spend 10-11 years instead of 7 years—if despite AIMA’s words, the regulations are written such that the 5 year clock starts from the start date of your first GV residency card). If you are anxious about the future, and need to feel that you are doing something RIGHT NOW towards plan B, but can’t move right away, then PT GV is for you. (But then if you would never give up your existing first world passport, nothing wrong with just a long term residency card somewhere with low maintenance and low taxes—having to renew every 2 years at 7k EUR is too much maintenance.)
I personally will not play games with day counting. Very easy to get caught. Visa fraud is never worth it.