A few additional notes:
Panniers are a revelation. You’ll try a backpack and be fine with it, but at some point you’ll get curious and will realise what you’ve been missing.
Tyres are a hotly debated topic, but for me, I will happily forgo a touch of puncture resistance for a tyre that doesn’t feel rubbish and/or has no grip (hello Schwalbe Marathon/Conti Gatorskin).
Lights have different needs to MTB lights, and to a degree, a few smalls ones are better than 1 big one. Their main focus is for you to be seen and not for you to see. I have 4 on the back (2 flashing, 1 constant, 1 on the helmet) and 3 on the front (one quite powerful one, one flashing and 1 other on my helmet). USB chargeable makes sense for the desk jockey’s amongst us. I’m also a big fan of spoke reflectors as they give some additional visibility from the side.
And finally, a quite lightweight hi-viz gilet is a brilliant bit of kit. Can be worn in a huge range of conditions and IMO you’re more likely to wear it than the standard bright yellow waterproofs.