Car detailing or driveway pressure washing? Please help me find what I need to do

So as the title says I’m torn between the two. I have a fairly low budget but nothing crazy, and I have means to increase the budget. But the main issue is the difficulty. driveway pressure washing sounds simple, but it’s one of those things that is very complex when you try to learn it. (Knowing what chemicals and pressure etc)

Which of the two is more difficult to learn?

Which is riskier in terms of damage if you mess up or are new?

Which has a lower startup cost? (I already have a smaller less powerful pressure washer, but if I want to do full on driveway cleaning I probably need a big one)

Which is harder to get customers?

Which has a higher profit margin?

About how long does the average job take?