Weird vibration at high speed, garage wants to replace half my suspension

So I've got this annoying vibration that kicks in around 100 km/h on my Camry, nothing crazy but noticeable enough that it's been bugging me for weeks. Took it to a place near my office and the guy barely looked at it before saying I probably need new control arms, bushings, the whole thing, quoted me something like 2,800 dirhams. That felt way too fast and way too expensive for something they didn't even properly inspect. My cousin told me to slow down and actually get a second opinion before throwing money at it, so I started searching around and ended up deciding to visit this page just to see what a proper diagnostic process looks like. Still haven't booked anything yet because honestly I don't know if it's really a suspension issue or something simpler like wheel balancing or a worn tire. Has anyone dealt with similar symptoms and figured out what it actually was? Don't want to get talked into a major job if it's a small fix.