Upgrading video card

Hi guys I'm wanting to upgrade my desktop's video card. I have the Dell Inspiron 8GB Windows 10 Desktop Computer (model #:I36553852BLK) I want the video card to be in the $80-$200 range (could go a little higher if the price is close to $200) and play PC games currently pretty dang good on a budget and better than the current  graphics I have. Of course whatever else I'll need in order to properly upgrade my video card would be very beneficial to me. When I first opened the desktop I realized that the current video card is embedded in the motherboard and I have to uninstall it from the desktop. (I know where to go for this but when the window comes up, it comes up with a check box stating "Delete software" something like that, should I click that check box or not?). What i did in the beginning was that I got this EVGA GeForce  1050 Ti graphics card with a 400 W power supply as i was told to get (Went to bestbuy). Went home and realized the graphics card ain't even going to fit. I went back and talked to the same associate I talked to previously and told him what happened. As he was telling me, he showed me what desktop I had in their store and he told me that it's going to be difficult to find a graphics card suitable for my needs. The associate also said that current and latest graphics cards out now have that "DDR5" and it won't fit in my desktop. Overall he suggested to look online for a variety of cards that will fit my desktop, and lately I haven't found any luck as to where to go and what to get in order to upgrade this difficult piece. I'm wanting to know what I need and what to do when I'm upgrading my video card on this desktop.

Thank you very much