Gotta be honest; I don't really see the merit here of trying to upgrade this. If you were using this laptop mainly for productivity tasks, that would be one thing, but for gaming it'll be your non-upgradeable part that's holding you back, not your possibly upgradeable one. So for gaming, it's not really worth the expensive and risk, and there is risk with any laptop upgrade. And while you can use an external GPU, it's janky unless you're using a Thunderbolt enclosure. Even then it's a bit on the janky side.
Laptops are basically disposable PCs. You use them until they no longer meet your needs. If you want a PC that upgrades over time, you want a desktop, not a laptop. Most people never even upgrade their desktops and there's just only a very tiny market out there for upgradeable laptops (else Framework would be a huge company rather than a small one).