There's customizable laptops
Gpu upgrades and ram upgrades but no motherboard upgrades . TBH i want one but i couldn't find good ones with the upgrade paths i need . I know a friend who built his barebone from scan.uk but i search their and can't find similar barebones their which give too many options . He said he got his barebone & motherboard from dell but dell no longer making barebones. Laptop barebones should be a good thing but i think the reason they're not marketed is that it will be cheaper than a full prebuilt not upgradeable laptop so they don't want that to happen . That guy who built his laptop has invested 1000$ in his powerful pc that runs 4k 60fps on most games but he has a 720p screen
. Anyways i can't find that worthy deals right now but it maybe in used markets.
I heard about Sager too i'm checking that now maybe i find some good things .
Its solved but i wanted just to say there's actually partly upgradeable laptops not fully but not only ram & hard drive . Even graphics cards .