It really depends on how much you were planning to lard up that Mac with expensive Apple memory and storage. The more of that you want or need, the better the PC is going to look. Ballparking:

  ATX case $100
  650W ATX PSU apparently these are the smallest now? $100
  Z690 motherboard you can spend a lot here but say $250
  Reputable DDR5 DIMMs: $70 per 16GB, $120 for 32GB, $220 for 64GB
  Reputable 1TB SSD $100
  Excellent and quiet air cooler: $100
  CPU similar in single-thread perf to M2: $400

You'll note the absence of GPU. I personally don't use them so I see no value in Apple's supposedly quite good ones. And we don't have 4x Thunderbolt ports that will set you back another $100. But we're up to $1200 which is noticeably less than any Mac Studio model.