Advice on residence permits

Good day everyone

I would like your advice on the following situation:

I am South African (thus non-Eu)
I have held a Belgian temporary residence permit for 3 years
I am now employed and living in Switzerland, also under the temporary residence regime.
I am employed full time as a gas engineer by a Swiss Company
My wife and I own a house in Villaviciosa, Asturias. My wife wants to use the house as a rental property and we would also like to spend more time in Spain with the view of eventually transferring our incomes and thus taxes to Spain. This activity is foreseen to generate 2 or more local jobs for our local village if the application is successful.

What type of residence permit can we apply for to make this happen? We are planning further investments in our house and potentially extending the property however we want to ensure we will still have rights to use the property.

Thank you for any insights.

Arco-iris