Im no expert on Canada, but in most western countries you dont need proof that you live elsewhere. The way it works is that you need to fulfil the criteria for being out of the tax net, typically by not having ties to the country you are moving from and not spending too much time there, after you move out.
With some exceptions, where you have moved to︀ doesn't matter, what they check (or make you show) is whether you have properly moved︁ out or not. You do usually have to give them an address abroad though, and︂ it is anyway useful to have an official address abroad for all kind of reasons︃ (for banks, EMIs, brokers, insurance etc). Id recommend having an official residency permit in the︄ country of this address. But to also get a Tax Residence Certificate from this country,︅ while it cant hurt, is I think usually unnecessary (unless Canada has some unusually strict︆ requirements).
You have to apply for a residence︈ permit, in Paraguay you get a temporary 2 year one at first, in the UAE︉ there are many different types of residence permits. Not too difficult to obtain in either︊ country. And in the UAE you just have to spend at least 1 day every︋ 6 months to maintain it (but even if you miss the 6 months deadline it's︌ no big deal). Paraguay also has very low requirements to keep a residence permit, but︍ like the UAE you have to apply for it in person.
About Paraguay:
"There is︎ no express or specific requirement for physical presence in the jurisdiction, however,
it is advisable️ to visit the country minimally twice during the initial two-year period." Source:
PARAGUAY PERMANENT RESIDENCE PROGRAMME , NTL Trust
If you want a tax residency certificate from Paraguay or the UAE you probably have to stay longer. For the UAE it's 90 days, but apparently it's possible to get it even if one is below the 90 days.