Socketed mobile CPUs aren't a thing for the past couple generations. The last one I remembered was the Core 2 series. So an upgrade now is a big jump, especially if you go for something with DDR5 memory.
Framework is going to be your best bet if you're looking for an upgradable platform. The CPU is not socketed but they have provided 3 generations of Intel CPUs on replaceable motherboards already since their inception, as well as an AMD version. Their 16 inch will be a new form factor and platform but based on their track record so far, I expect them to support this form factor for a while as well.