I prefer to put a Limiter in the output inserts and also adjust levels by using the gain trim. This is because I work within Cubase at a conservative level. I then watch metering carefully and get the final output level where I want it to be. Then render.
2 You have a choice when rendering, you can select any path. I usually mixdown to Desktop. If I am rendering and re-inserting into project, then I am careful to check that I have changed the path to the right location.
I never normalize using the normalize function. The reason is - Independent of cubase - that normalisation is usually not really what you Need in order to adjust the Overall volume of a track.
I dont want to get into Detail too much here, i advise to read some articles about mastering. This will not bring us/you to a Level of “mastering” but help to understand how to achieve volume and Dynamics.
Avoid normalizing, it just sets your audio up to get clipped by something once it’s out in the wild. Use a limiter (brickwall maybe) as the last plug on your output (or just before dithering if you are doing that at this stage) to give yourself a bit of leeway from maxing out the signal. Judiciously use compressors on individual tracks, groups, and the output to increase the loudness. Google “audio volume and loudness” to read up on the differences between the two. I think Cubase has a video about the Loudness Meter (but not certain).
Normalizing is like wearing a pair of pants that you can just barely squeeze into vs. a pair that has a bit of room in the waist. One of those is going to make it a lot easier to bend down and tie your shoes.