Any production SUP is going to weigh 10kg or more. If it's cheap or old then definitely more.
That's only a problem if you have to lift it above your head, or carry it for a long distance.
Overhead lifts can be a drama, but you can deal with it by being smart about storage and transport. There are techniques for getting heavy things into overhead storage, or just avoid it (Prop one end on the roof rack. Transport it inside the car. Store it down low.)
For long carries you can think about shoulder straps, taking lots of rests, get help, or again just avoid it. You can get leash plugs put into the rail or deck so you can attach a strap.
An alternative option is to consider a custom SUP from a local shaper. My SUP is feather light and much cheaper than a brand new production SUP. It has lasted really well and is great in smaller surf. It had to visit the board doctor after wiping out in bigger surf.