Two Computers Hardwired- 1 Cable Modem?

Ok, I have my desktop PC in my office on a dedicated hard line.
Wifi is in the house but signal is weak (can't even stream Youtube) out in the office over wifi.

In the "old days" cable modems had more than 1 port on them, I remember my brother in law coming over and he could plug his laptop in and we would both be rocking off the same modem- both hard wired (My desktop and his laptop.)

New modem only has 1 Ethernet port on it. I would like to run my laptop and Desktop PC off this one modem (hard wired for both)

Would also be nice if when I bring my work laptop home I could just unplug personal laptop off hardwired connection and run my work Laptop off that connection.

Any tips?