So many options!
I like the MX68 (it is a model down from the MX75 mentioned by @GreenMan ). It has 10 x LAN ports, 2 of which are PoE. With 5 computers, you could plug them all in.
https://meraki.cisco.com/product/security-sd-wan/small-branch/mx68/
There is a more expensive version called the MX68CW, which has cellular and WiFi built in.
https://meraki.cisco.com/product/security-sd-wan/small-branch/mx68cw/
The most popular licence for the MX75, MX68 and MX68CW is "Advanced Security".
If you wanted to go much cheaper, there is also the Z4. It has 4 LAN ports and built in WiFi. Because this is a lab, I would get either a "Advanced Security" or "Secure SD-WAN Plus" licence.
https://meraki.cisco.com/product/security-sd-wan/sd-wan-teleworker/z4/
This sizing guide lets you compare all the different models.
https://documentation.meraki.com/MX/MX_Sizing_Information/MX_Sizing_Principles