I'm jealous sometimes of my girlfriend's Samsung ultrabook for this same reason. I think it's Samsung's answer to the LG Gram and wow, it's light.
If you want a really light machine, don't you have to ditch the aluminum? My 2017 MacBook Pro gets heavy, esp once you add the charger. I take it everywhere.
Would you consider getting something like a LG Gram 15" then? It's thin and light but appears highly repairable [1]
[1] https://www.ifixit.com/Guide/LG+Gram+15-Inch+Repairability+A...