There’s a lot of good advice on this thread.
Without wishing to underestimate your skills, it sounds like you don’t have a huge amount of experience in bike maintenance.
Which is fine. Everyone has to start somewhere.
One of the best things you can do is to look at the things people have mentioned.
- Ensuring you know how to adjust your gearing.
- And removal and refitting the rear wheel.
These are very different skills to doing this on normal bikes, so they’re good to learn in the dry and warmth of your house/garage - rather than on a rainy, dark morning when you’re already running late.
Neither of these things is difficult, but they’re not exactly intuitive.
Here’s how to adjust the gears so they index properly.
View: https://youtu.be/-mGfuqxilO4
And here’s how you remove the rear wheel.
View: https://youtu.be/ZfsLis3_JLw
As for tyres, I switched to Marathon Plus once my originals had worn down as I was more interested in fit and forget ease of use rather than outright speed.
Having said that, I’m not exactly slow on my bike. Most of my commutes will average out at 15mph+ and my normal moving speed is about 17mph.
And I’m almost 50 and 16 stone.
Depends what you want from your bike. If you’re entering a Brompton race, then the lightest tyres might make sense. But for a commuter bike, getting where you want to be on time makes more sense to me.
Other people have different views, but I’ve not had an actual puncture in 4 1/2 years and 10,000 miles.
Good luck with your new bike.