There’s been a lot of interesting content in this thread, however still not enough to completely clarify my position. In regards to Article 14 of the OECD model tax treaty:
(1) Income derived by a resident of a Contracting State in respect of professional services or other independent activities of a similar character shall be taxable only in that State unless he has a fixed base regularly available to him in the other Contracting State for the purpose of performing his activities. If he has such a fixed base, the income may be taxed in the other Contracting State but only so much of it is as attributable to that fixed base.
What if I say have an office or renting a co wroking space in the respective country? What if additionally a small percentage of my self employed income is actually taxed in that country because it is “attributable to that fixed base”, meaning I was working there for a few days a year?