hello; my inquiry is related to immigration and foreign companies

my tourist visa has been extended until Sept 26th, having enter to the country on February 28th with a 3 months tourist visa later extended because covid and then for another reason (but also January has been inside VN). I’m Spaniard. My questions are:
1.- for how long can I ask for more extensions? (I mean with the new rules in case they are applying to my situation)
2.- with this status, could I get a work permit and resident card not going out of the country in case someone offers me a job?
3.- either being in the country or going out for a few months and coming back later, I would like to explore the options to legal or formally be able to develop some project, do some kind of business between Vn and Spain or just working or living in here by myself for longer periods than 3 months (but not through an investment of 140k USD amount).

Thank you for your attempt¡lion