Segregating web and app activities with multiple PCs

Multiple WAN links and multiple machines don’t really buy you any additional privacy, but there are good reasons for backup hardware and connectivity regardless. With more hardware you can also run more services locally, and this does meaningfully increase your privacy. This includes file storage, Internet-of-Crap substitutes, email, perhaps some AI models if you have good GPUs available. I don’t use any cloud services at all for my personal stuff. Note that you don’t necessarily need more or new hardware. Don’t be afraid to work the machines that you already own harder. Any desktop, preferably running Linux, can do all of the above while still serving as a normal workstation.