@philthaiven temporarily non-resident means that you spent <5 tax years abroad, so yes you pay on your return. If you return to UK tax residence within 5 tax years then you weren't
temporarily non-resident. It's just semantics.
Portugal NHR has not been getting great reviews, but Portugal and Germany can have a favourable lack of CGT for tax residents. I don't know much about Portugal but if you've held your crypto for years and sell it while resident I don't think you're liable. Of course, these rules could change, especially with EU pressure to harmonise which is why I would be more drawn to Georgia︀ with a ruling, or UAE.
Dubai
legal residence can be a handful of days, with︁ no 183 gap but doesn't UAE require 180 days for
tax residence, at least︂ for the first year? Legal residence gives you access to local banking without CRS, which︃ isn't the same as tax residence but might work out for you (see Fred's reviews)︄ and in your case CRS doesn't even matter as you're not worried about your previous︅ country finding out (because you're staying away >5 years).
The thing I don't understand is︆ the idea of "remain tax resident with limited time in the country". Perhaps it helps︇ for banking, but I'd say it isn't relevant to the UK's statutory residence test. Some︈ places that do take into account a tax residence elsewhere (e.g. Cyprus, Thailand, Georgia) seem︉ to require 180 days for it to count anyway. I don't doubt that some places︊ accept Georgian HNWI status with limited time in the country but I'd be careful about︋ the detail. If you want to spend decent time in some country in a year︌ when you're cashing out, then I'd say look at the specifics of that country.