Good analysis !i read the whole thread so here's my comments...
one of the reasons for moving away that you have mentioned was the handling of the boomer coof there. i don't want to burst your bubble, but that crap is happening all over the world. the timing is just different, that's all. so don't use that as a reason because there are no real options and when SHTF again, same totalitarian behavior will happen yet again - everywhere.
from the conditions you have set, you have only two choices - continental europe and continental america.
if we look at america, the entire north america must be crossed off the list since it is high tax with high costs of living.
south america on the other hand was historically very commie oriented and violence is prevalent to this day. so i would cross that off the list as well.
so we have europe, which you said you would prefer. europe really loves its socialism and not is falling in love with fascism yet again. but lets just ignore it for now.
income tax will mess you up in europe like nowhere else BUT what will finish the job is the healthcare and social security that will thanos snap half of your income right away. so that is not an option.
hence, we have to look at the dividends income. and i am really talking dividends, not capital gains here(ie. active investments).
in this case, we have some options. Dividend Withholding Tax Rates by Country for 2020 | TopForeignStocks.com
if you will be active, then income tax, healthcare and social security has to be take into account. Tax rates in Europe - Wikipedia
andorra, bosnia, bulgaria, georgia, montenegro or ukraine could work.
if you will be passive, then portugal's and cyprus' non-dom will work out the best for you. unfortunately both of them have high property taxes, if you would want to buy a home there.
cyprus will give you the option to be tax resident with only 60 day stay, instead of 183 day, with certain conditions applied.
you have mentioned that you would be domiciled in cyprus and live in barcelona for 6-8 months. but you are forgetting the tax residency which you would gain in spain and lost in cyprus with this setup.
so to tl;dr figure out your source of income first and based on that you limit your options. then you can read up on individual countries and their tax approach to your source of income and then you can decide.
personally, i am looking to get away from EUrope because it's free fall from here on. asia is the future, the west is done, pendulum is swinging to the east yet again. so personally i am favouring malaysia right now.
ps: there are some EU countries that have 0% CGT if you hold long enough. usually no less than a year(this is CG not dividends though).