The mxm big laptops died the only seller I know of right now is eurocom but they're still on 12th gen intel desktop cpus and the 3070ti at best https://eurocom.com/ec/configure(2,486,0)RaptorX15
I used to have a tornado f5 then a sky x7c; upgrades were barely supported and mxm standard was changed so much it never mattered and you just had to buy another entire laptop usually after two generations and sometimes they never got an upgrade like right now theres no mxm 40 series I know of.
Only realistic thing you can really do is eGPU stuff in which I would reccomend you get something with oculink over thunderbolt.
You could wait for the framework 16 but thats a long wait.