A:AnswerHey man! This prebuilt computer with these exact specs will be MORE than enough. I've had it for over 2 weeks now. It's been amazing. The thing I will let you know though is that for audio mixing, you'll need more ports. There is only one USB-C port. although there are many 3.5mm jacks for speakers and audio, I'm currently using a DAC with passive speakers.
A:AnswerWarning about adding addition Graphic Cards to this case. My understanding is the included Graphics Cards are shorter than a regular stock cards.
Make sure to measure your case first before buying a second GPU and probably check with Dell website to make sure it will fit also.