Kia quoted me for a whole new AC system, second opinion needed

My Picanto's AC stopped blowing cold last month and the dealer quoted me for what sounds like a complete system replacement, compressor and all. That feels like a massive jump for a car that's only a few years old and was working fine until suddenly it wasn't. I want to see more about what a proper Kia specialist would actually check before jumping to the worst case, so I've been looking around for a second opinion rather than accepting the first quote. Has anyone had an AC issue where the dealer wanted to replace everything and an independent found a much simpler fix? I'd rather spend a bit on a proper diagnosis than commit to a huge bill if it's just a leak or a sensor.