The difference in weight between a light and heavy bike isn't that significant. The lightest ones are maybe 7-8kg and the heaviest at 20kg. The hardest part is how awkward they can be to carry. I had a 15kg folding bike that I carried up 5 flights of stairs to work by hooking the saddle over my shoulder, and a co-worker set up a luggage strap on his so he could carry it up 4 flights to his flat on his shoulder.

I think if you can get part of the frame over your shoulder then the weight shouldn't be too much of an issue, and you'll find it much easier over time.

For a lightweight do everything bike, I'd be looking at the Boardman URB 8.9 hybrid:
https://www.halfords.com/bikes/hybri...es-426918.html

It's got a belt drive which is a bit lighter and lower maintenance than a chain, and should be capable of anything up to fairly aggressive off-roading. It comes in at 10.7kg which is pretty light (my gravel bike at double that price is 10.4kg)