This Pepe is selling hot air. Do not fall for it!
What he is doing: Mixing residency with tax residency. Just because you have a residence permit (in the case of PY not even a permanent one) doesn't mean that you can claim tax residency. If you do not stay 120 days in PY you are simply not a tax resident in that country.
To be honest, he
isn't selling or claiming to provide tax residency. Noone can truly "sell" tax residency anywhere in the world - with the exception being maybe a bribed government worker who issues you a tax residency
certificate.
He is selling a service - consult with you and help you to get residency in Paraguay (seems like before it was permanent, now it is first temporary and after a year or so permanent).
What you do with your new shiny residency is up to you. If you need tax advice, ask a tax advisor, not a Youtube guy selling some consulting service and helping you with residency paperwork.
I'm pretty sure the tax residency can be achieved even without spending 120 days there. I doubt it is fully legal and according to the law but it is possible. You just need to know the right people.
It is the same story with UAE, Thailand and other countries like that - you can get a residency permit easily but to be a tax resident you should meet certain criteria (spend days there, have documents such as long-term rent etc) to be issued a confirmation or a
certificate that you are a tax resident there. Yet mysteriously, people exist, who have this
certificate and spend only 2 days per year there. I'll let you guess how they achieve it.
Later, when you have this residency in a country that doesn't tax any income or taxes only locally sourced income, you should check what your situation in your home country is.
Do the countries have a treaty for avoidance of double taxation? If yes, make sure you
meet the criteria to be the resident of the new country. If not, make sure you do
NOT meet the criteria to be the resident of the old country.
There is a lot of misleading info and nonsense in this topic, some text in posts from JustAnotherNomad etc... but I don't have the energy to go into detail.
@backpacker don't get so angry
evidently many people are going this route.
To answer OPs question
"what problems can come up later if this setup is legal right now?": there is nothing illegal about this setup. If you truly don't live in your old country, you can become a resident of Paraguay. If you want to keep living in your old EU country and fake it, then a lot of problems can come up later. If you are an US citizen or US person, then none of this applies and you cannot use it.