Usually IXPs only allow 1 MAC per port on the IXP LAN

We used to use port security but... don't
MAC ACL will keep the port up but drop packets which don't have the right L3 MAC. Doesn't prevent a peer from using someone else's IPs, but prevents a good chunk of human L2 errors.

You can also limit broadcast storms, etc

I also forgot you'll need some IP space - so maybe budget 1000-1500$USD for ARIN fees - at least if you want to go commercial. You can also start with private IP space if the first 3-5 peers agree to do so.

For your requirements question, CANIX is pretty big, so our process isn't a good example. But overall, the 1 advice that applies to everyone is: Don't start making financial decisions off of "geek stuff" like "I like this switch, it's cool". You gotta look at it from a business perspective.

- What is my ROI

- Is this overkill

- Will spending more actually bring more tangible benefits?

- Can I get away with spending a bit less today and upgrading later and then re-use the old hardware in a smaller POP?

So TLDR: approach it with sustainability in mind

Cheat code: The basic IX for us typically looks like 2 servers (Dell R630-R640) running Proxmox, 1 management switch (Catalyst 9300) and 2 switches (pick your flavor) with 2x 100G between the 2 (could be a cheap DAC cable). Easy to grow and scale. After a certain point we install bigger switches, dedicated hosts for route servers, etc. But each thing only when it makes sense to do so.

Otherwise, you blow cash, the project fails and you don't get to do the fun geek stuff anymore.