Need advice on cashing out crypto for a private vehicle purchase in Spain

Hey guys, hoping someone with local experience can help me out. I’ve been living in Spain for a couple of months now, and I’m finally buying a used scooter from a private seller here to get around the city easier. The seller is an older local guy who explicitly wants the payment in cash Euros—he laughed when I asked if he takes bank transfers or crypto, typical old-school Spaniard haha. The thing is, most of my spare money is in Tether. Does anyone know the safest way to convert usdt to eur madrid for a cash handout? I need a solid, step-by-step manual or a verified service because I really don't want to carry an envelope of cash to some random street corner from a sketchy forum ad. How do expats usually handle large cash-outs here securely?