Please help me fix my computer.

[dubsflick]

So I bought this pre built dell system the Dell G5 5090 https://www.dell.com/en-us/shop/desktop-computers/dell-g5-gaming-desktop/spd/g-series-5090-desktop having an i7-9700 and a 2070 super back in July of 2020 and had not a lot of knowledge on pc's and I'm noticing big performance issues in the fans getting way to hot and very loud and I'm looking to replace the fans and maybe get a new case and add some more fans.

How would I find a case that would work with the parts I have and find good fans for it. 

[Draconid]

It looks like it'll be quite difficult to change your case based off the image of your motherboard, it seems that the front panel is soldered directly to the motherboard and the rear io shield may not be removable.

As a result if you want to change your case which I highly recommend as it looks like there's only one rear exhaust fan, you're gonna have to get a new motherboard that supports your CPU. If you do decide to, find yourself a motherboard with a LGA 1151 socket (so something like a Z370 or Z390 motherboard.) 
Otherwise I don't really see a good way of using your current motherboard in a new case that would be pratical and wouldn't require you to cut stuff up. 

[dubsflick]

do you recommend any other motherboards or cases 

[Draconid]

21 hours ago, dubsflick said:

do you recommend any other motherboards or cases 

I'm not super familiar with lga 1151 motherboards, so I wouldn't be able to, but there's a ton of reviews and guides out there that can send you in the right direction. As for a case, go with whatever one you like the look of, and it looks as if it should have good airflow.