How do!

Been a while since I have posted but could do with some advice
Basically I have always wanted a bike but due to family and work I had to go car instead but now I've decided to do as I please so I'm looking at getting a bike ideally the start of next year so I can take advantage of a full summer just need a little advice on what to go for as I know literally nothing

I have never ridden a bike so I've been divided between just doing my CBT to build my confidence for that I've been looking at a Honda Grom size wise and everything think it would be a good fit as I'm not very tall and I'd much rather be able to comfortably touch the ground or as my mechanic suggested since I can just go full licence he suggested a KTM 690 but I have been eyeing up a Honda Rebel 500

Once I get a bike it will pretty much take over as my daily so need something with atleast half decent MPG, comfortable to ride, not bothered about crazy speeds but a little power for overtaking would be nice (alot of slow drivers in my area), if I could do most of the maintenance myself that would be nice but not really bothered about that much and any recommendations for insurance would be grand if i could do my car and the bike through the same people then even better currently with direct line for my car but can't seem to find anything about bike insurance with them

I'm genuinely torn between what way to go so any words of wisdom are much appreciated!
Many thanks!