Replacing a laptop screen is easy enough if you can swing a screwdriver (open the thing up, get the numbers off the back of the panel as things could vary between the same model, I suggest not going to amazon nor ebay and instead going to a proper vendor, put back together in reverse order making sure to be careful with the ribbons and cables, in case of old laptops be aware that the backlight inverters can be fairly high voltage).
Upgrading screens on laptops however is a weird thing. Most laptop makers don't make or custom make their own panels and instead buy them off the shelf from one of a handful of companies.
Traditionally you would want to replace the screen with the same model it started with. Your only choices were matte or gloss, or maybe a panel with a calibrated colour space. On rare occasions when higher resolution screens were available as an option (it was sort of seen in the P4 era, then all laptop screens became awful* and today we are seeing some things again be good) then if you could find out the right numbers then you could install that, though you might still have had to find a new ribbon.
*seriously it sucks. P4 era I had stuff along the lines of 1600-1050, during the core2 era then 768 high was common even among the higher end laptops.
Today a lot of things have moved to embedded displayport which makes some things a bit easier than the handful of quite odd standards seen in the past. Though you still risk having to fiddle with new ribbons rather than a drop in replacement. Afraid I don't know the specifics of the Dell G7 though and most probably would not -- usually if the option arose I would have to go to a parts vendor and service manuals for the specific model and spend some time figuring things out.
like a 250 dollar kit back when DDR4 was Intel only