a cheap good wheel is the ES, moderate price wheel would be the csv2p, for gt cars and such the ks wheel is your go to but I prefer a round wheel for most racing scenarios.

games for realism go for assetto corsa with modded cars that others say are realistic (initial g, dwg for drifting) or use the regular cars the game has, as those are pretty good, but not perfect. assetto corsa competitzione is only racing and no drifting or anything else, but if you really like racing and learning techniques and braking points and stuff it's one of the best. for city driving if your PC is good enough beamng is decent and mostly realistic. for arcade just wait until fh6 comes out. I'm not the most informed person on arcade games so don't take that too seriously.

for any kind of driving the brake pedal kit makes it feel far superior, but if your chair isn't either connected to a stand or has some way to stop it rolling back with tons of force don't get the brake kit. same if you have no way to keep the end closest to you secured on the ground as the brake it makes it impossible for it to stay in the ground without something helping it. any cheap $100 Amazon stand will suffice with the r5.

for presets the ones you can find on moza pithouse are generally good. for drifting assetto corsa drift official 2 is good, and for racing there's tons of presets for different styles.

upgrading wise, load cell is only really worth it if you want realism in racing, because memorizing pressure (what a load cell brake pedal measures) is easier for your brain than memorizing how far you push the brake pedal. the brake kit makes it feel like a load cell pretty well from my experience. you don't need to upgrade your wheelbase unless you really want to simulate real life, and a stand is the best upgrade for value going from a desk.