Poorly looking cat

So there is this cat in my neighbourhood and I’m not too sure if they have an owner/ who they are but this cat is so scrawny and looks not fed well compared to my little fur baby and idk if they are male or female but they also have this hanging belly it’s almost like a big hanging belly near the back legs, it’s really low and swings whenever the cats wants and it looks like they struggle to walk with it. So the cat is skinny and bony but has a swinging belly? I really want to do something like feed it/ take it to the vets just to see if they are okay Cus I don’t want to leave this poor cat looking like this. No one wants a cat looking bony and skinny and not a beautiful fur baby. What should I do? I want to give this cat all it needs Cus I know I can. Unfortunately I don’t have a vid of the belly but it really does swing and it’s big

Hello - my first concern would be whether this is simply a healthy mother cat who is currently feeding kittens.  Some mother cats do move away from home slightly to choose the best territory they can for their family at this time.  Therefore, as long as there is no obvious illness, I would start by asking around locally to see if anyone can identify her.  If the situation continues and no-one locally seems to know anything, there are charities and local councils that might lend a scanner in order to check for a microchip on this cat and contact the owner. This is probably better than taking her anywhere at this stage.