I purchased a sovol sv07 and software wise it was a total trainwreck. After fighting with the company over a faulty power supply (about 3-4 weeks for them to confirm the issue, ship part and me to receive replacement), I ended up giving up on their support and using a raspi with regular klipper and the printer.cfg from the original controller to bypass their locked down version of klipper and now the machine is great, but sovol ain't it for support. That said, they release the source for every other printer (not the sv07) and I'd recommend that you find out how much community support that sv04 has before buying.
I purchased a sovol sv07 and software wise it was a total trainwreck. After fighting with the company over a faulty power supply (about 3-4 weeks for them to confirm the issue, ship part and me to receive replacement), I ended up giving up on their support and using a raspi with regular klipper and the printer.cfg from the original controller to bypass their locked down version of klipper and now the machine is great, but sovol ain't it for support. That said, they release the source for every other printer (not the sv07) and I'd recommend that you find out how much community support that sv04 has before buying.