Short answer? Yes. Long answer? You might use up a good chunk of that 48 hours learning about setting up a gateway using a *nix system. But basically, connect your linux/bsd (pfsense is probably the best option) to your hotspot, connect your wired ethernet card to your existing home switch (or wifi access point -- most likely it's an all in one anyway), and throw a few lines of code in to manage the routing.

This article doesn't look like a bad place to start: https://brendonmatheson.com/2020/08/07/wan-failover-to-4G-with-pfsense.html