Checkout framework laptop [0]. Pretty sick. It's a really modular laptop focused on reusability. I would order one if they accepted crypto.
Thinkpads have a pretty good reputation. You can also get big "desktop in a laptop" style PCs, and generally, the thick gaming laptops tend to be easy to work with. You can look at Clevo, which is known for being the OEM for many off-brand PCs, notably System76. If you are a bit more extreme, you can look at Panasonic Toughbooks: hardened, industrial laptops with plenty of swapable modules.
Framework have the advantage of being thin and light, most modular laptops are on the big side. It means it fits a niche. However, if re-usability is your goal, keep in mind that it is a startup, it may fail, and if that happens, forget about support and spare parts. By comparison, Lenovo is not going anywhere.
I confirm, I havent bought one yet, but the other day I saw this laptop:
https://www.amazon.com/ASUS-IPS-Type-i5-10300H-Keyboard-FX70...
17 inches, a 144hz screen,GTX 1650, 512 GB SSD and space for 2 more!. You can add a 4 TB HD, a 1GB SSD, and change the RAM to 32 GB and get a monster machine for about 1200 USD.
With a Clevo (and other similar brands) you can have even more customization options, although I expect them to be more expensive.
A cheap B450 board will last me a decade at least. Start with a 2700x, upgrade all the way to a 12 core or even 16 core Ryzen 9. No thermal issues.
64+ GB of RAM, plenty of room to play with voltages and clocks everywhere, will actually run Linux without ridiculous issues.
Wifi handled by an external router with dual radios and Openwrt. Add a Li-Ion UPS if I'm going to a place with bad power supply.
I swore off desktops for laptops a decade ago but then they turned to locked down shit. No thanks.