NixOS is the sort answer. It’s reproducible across hardware. But I’ve never tested it.

And the download page is so simple

Do you have desktop or laptop?
For desktop, I recommend getting an HDD for storage. They’re cheaper, I bought a 4tb Seagate Ironwolf for less than 100€.
I also have a 1tb nvme, where I store things that require fast reads like my gaming collection while the system is installed in an SSD. (The parts were not bought at the same time). For laptop, you might want to stick to what you have inside and just get a good external USB. The usual brands are still good and I think prices have flatten across the industry.