Buildapc

This is the equivalent of vlog youtuber buying a 1500$ Mac to do basic video editing. If your only goal is to do music production you don't need these kinds of specs. A prebuilt 500$ ibuypowerpc would be more than enough. you can spend the 700$ on some nice equipment and professional software.

Unless youre a hardcore video gamer or into super specialized tech like locally hosted AI or crypto mining you don't need to spend more than a few hundred bucks with today's modern hardware. 8gigs of ram, an amd processor, and a graphics card made in the last 10 years will service you just fine. As a music production person your biggest concern isn't processing power but hardware fedelity. You want to spend the big bucks on your synth, cabling, production software and sound card if applicable. Also look into open source production programs if you find one that works for your needs you can save bucks that way too.

My priority would be to put more resources into the audio interface, controllers, and storage. I think you'll be fine with just about any modern build. Maybe lean towards the quietest build you can make.

If you're serious about your work, I would do a separate drive for storage of your media. Keeping the project data off of the OS drive. I'd even do a backup drive. I don't think there will be a performance benefit. I just prefer a neat file system. Especially if you're working with audio clips. Audio files don't take up a crazy amount of space. I feel it's important to have backups if you're collaborating with others.

The stock CPU cooler should be okay to start but you might start running into thermal problems after an extended period, especially with heavier multi-track projects. YMMV, but if it's in the budget it's nice to have thermal overhead and have it run quieter.

I'm not an expert on DAW software, but iirc, it involves loading a lot os small files, so I'd recommend a PCIe gen 4 ssd with high iops. Something like a WD black sn850x or a Samsung 980 pro.

Also, you should be able to save some bucks on lower wattage PSU. On a side note, what do you need the USB expansion card for? The motherboard comes with some fast USB already. If you do need it, make sure that the slot on the motherboard is electrically wired up with the same amount of PCIe lanes. On an another note, I'm not sure where the sweet spot of ram speed is on intel, but on AMD it is 6000 and Intel is higher than that. So you might want to get some higher speed ram as well.