Devices similar to what you are asking for are out there now, in recent years the market for these devices seems to have exploded. I recently built something si

Devices similar to what you are asking for are out there now, in recent years the market for these devices seems to have exploded. I recently built something similar to this one with i7 of some generation or other and quad 2.5gbit NICs etc. They are available in all sorts of neat fanless configs and a range of CPUs, and generally have no issues saturating all 4 ports at peak speeds etc. I just pulled the first hit from Amazon for "vpn appliance": > https://www.amazon.com/SENSTUN-Firewall-Appliance-Fanless-Barebone/dp/B0BWVBVFT3/ref=sr_1_1_sspa?crid=3APVAWU5WZH5T&keywords=vpn+appliance&qid=1689108984&sprefix=vpn+applian%2Caps%2C210&sr=8-1-spons&ufe=app_do%3Aamzn1.fos.304cacc1-b508-45fb-a37f-a2c47c48c32f&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1 https://www.amazon.com/SENSTUN-Firewall-Appliance-Fanless-Ba... Being that they are just PCs, you can install pfSense or whatever solution you want. They are silent and no larger than a typical network switch. If anything, the enthusiast firewall market has been well served recently - there are well over 20+ models on amazon alone right now intended for homemade firewalls or routers.