Check the Park Tool Repair Blog front derailleur adjustment and rear derailleur adjustment articles.
It is normal for it to rub if you are cross chaining, and even if it's not rubbing, you should not cross chain because it wears out the components more quickly. Cross chaining is being in the biggest ring and one of the biggest cogs, or the smallest ring and one of the smallest cogs.
"Factory settings" isn't really accurate, bikes are generally not fully assembled at the factory, they are fully assembled at the bike shop and the mechanic who assembles the bike fine tunes the adjustments before selling the bike. If it's a shit mechanic then yeah you might have a new bike with derailleurs that aren't adjusted right.>>1652401
People still do patch kits. Best way to avoid flats is keep tires inflated. Tires lose air over time just sitting so make sure to check tire pressure before each ride or once a week. Riding at low pressure means the tube moves around a little inside the tire which makes it prone to getting flats.>>1652405
Are you sure you adjusted everything properly? Nothing is rubbing? Are all your parts compatible with each other? Did you do a really good job cleaning out the bottom bracket shell before installing the new bottom bracket? Get new bottom bracket tight enough? Grease the new bottom bracket? Did you replace the chainrings and if not did you make sure your chainrings aren't bent and your chainring bolts aren't loose?>>1652428
They're not horrible to ride, but they take getting used to because you're going to a bike that is much lighter, much narrower tires, higher tire pressure, and drop bars. A lot of changes to get used to. They aren't difficult or dangerous after you get used to them. You could go with an in-between option like a cyclocross bike or an old steel road bike.