Flat-bar vs drop-bar makes no difference. Aero sure does and it is easier and more comfortable to stay aero on drop bars ..... a lighter bike makes very little difference unless you are climbing 10-percent hills all day.

Lighter wheel s and tires make much less difference than aero wheels and tires ..... unless you are climbing ten-percent grades all say.

Rolling resistance makes some difference, but like most "marginal gains" categories .... a few watts from aero socks, a few watts form faster tires, a few watts from matching the width to rim width ..... but for most less-than-all-out riders, none of that stuff makes a huge difference numerically.

The biggest factor is how you feel and how the bike feels to you. If the bike feels lights and fun and fast .... you will have more enthusiasm and likely ride a little faster, put out a little more energy, because you are happier and feel more energetic. The actual numerical gains, the quantifiable gains, might be tiny and almost certainly will not be huge ..... people who think they will be faster on their new bikes ignore the fact that 90+ percent of performance is the engine.

I have done back-to-back switches between bikes with ten-pound weight differences over an identical route .... and as a rule after a few minutes I don't feel the added or reduced weight, because I am only responding to the immediate responses of the bike I am riding ... and there is not a regular, dependable performance gain with on bike over the other, probably because if I am having a bad to day today even while riding a lighter bike, I will not be able to keep up with me of tomorrow when I am on a heavier bike but having an awesome day.

I track pretty much every ride on a spreadsheet and have GPS traces so I can see how fast I was going at any point of the ride .... maybe if I rode a lot of ten-percent hills ... but on my normal routes, the bike I choose is a lot less a deciding factor of how fast I go than my attitude.