Residencia

Your post is contradictory.

You say you have been "living" in Spain for 5 years, yet have not been in Spain for >183 days/year and were a tourist.

So you were not ordinarily "living" in Spain.

Your claim of Residency status as at/before 31/12/20 may hinge on whether or not you had health insurance in 2020 (assuming, of course, that you can firstly demonstrate routine expenditures on housing, utilities, groceries, petrol, etc.).

If not, you weren't meeting the criteria for Residencia/TIE.

If you fail to meet the criteria for Residencia/TIE as of 31/12/20, the new (post Brexit) process, rules and financial requirements are considerably more demanding.