The advantage here is having a wide variety of experience outside of Cisco lock-in with open software (normally Linux based, some are based on *BSDs) and the actual software license is free and open for the most part. You also will get a full linux distro with a familiar cli so you can run automation and config management code directly on the switch, which would help you learn multiple things at once. Also it doesn’t hurt that you’d get 10 gigabit, or even 100g(!), Ethernet for your homelab for super cheap :).
For your shopping, look at the SONiC hardware compatibility list [2], often you can find lots of these for cheap. Pick up some cheap and solid optics, fiber and whatnot from FS. [3]
[0] https://github.com/sonic-net/SONiC
[2] https://sonic-net.github.io/SONiC/Supported-Devices-and-Plat...
Meantime - if your target is specifically learning/certifications - have you tried the virtual labs?
https://learningnetworkstore.cisco.com/cisco-learning-labs
https://learningnetworkstore.cisco.com/cisco-modeling-labs-p...
They are not “free”, but the pricing does not seem to be too bad if your goal is the certification.
You can also search for “GNS3” and see what pops up :-)
I would argue virtual devices are the most friendly approach e-waste wise.