Compressed air blowing is just a temporary fix at best, and you're right to be skeptical. After three years without cleaning, dust didn't just clog the cracks - it's settled on the radiator and fan blades, where air from a can won't reach. The noise is telling you exactly what's happening: the fan is spinning at max because it can't properly cool the console through the layer of grime.
Being afraid to take it apart is totally normal, but honestly the PS5 is actually pretty intuitive to disassemble. The side panels come off without any tools, and getting to the fan is straightforward. If you're really unsure, just watch a YouTube tutorial at 1.5x speed - it'll take like 15 minutes. All you need is a Phillips screwdriver and a can of compressed air for a final blow-out. If you're still nervous after that, yeah, take it to a service center - but they'll charge you, and the procedure itself is super simple.