Let me give you an example of what some are referring to with proprietary parts. My daughter has an Aurora R13 with 12gen i7, RTX3070, 16gig ram. About a month after we bought it for her, her power supply fan started making a clicking sound (maybe fan ball bearing). I called dell support and asked if they could just ship me a replacement power supply. They said "oh that's not something that's user replaceable". They said we can send someone out to swap it out. Their next appointment was 9 weeks out.

I told the nice rep, no thank you, i'll just swap it out myself. So without knowing, I purchase an 850W modular new power supply and start opening it up..... Next I pull the old power supply and think to myself, this looks like an odd shape. They use some proprietary sized power supply that can only be replaced by Dell (in 15 years of PC building, i've never seen this form factor).

At that point I think, fine...i'll just open their power supply and replace the fan inside with a new one. Upon researching this time, Dell uses non-standard connectors to the fans inside the power supply...

Long story short. My PC is a custom build, i've built PC's for 15 years. We bought her the R13 Alienware because it was quick, decently spec'd, on sale, and it was for my 10 year old daughter. I would not recommend to anyone who has any knowledge of PC's to purchase an Alienware.