In theory yes. Until you get caught. At which point you put yourself at risk of violating terms of the visa and losing the whole thing. Wouldn’t that suck?
it’s going to be the little things that get you. You are in an AirBNB for 2 months, you want to stay for another 6, you go to sign a longer lease, landlord asks for your visa, oh it’s the wrong one, sorry, can’t rent to you. You get in an accident in your car. Police looks at your ID. You don’t have enough wits to give the right evasive answer because of the accident, you give the wrong answer, you get investigated. You need to go to the doctor, someone asks for ID, you give the wrong answer, nice doctor doesn’t care but her snoopy assistant doesn’t like no’ furriners and calls the police. Can you get away with it? maybe. How good are you at it and how much is it worth to you versus just getting the right papers?
Borders appear to be re-appearing in Europe now anyway, thanks to covid…heck, soon, if you’re Irish, you won’t even be allowed to leave…