Its a small difference, but a real one.

Go into your operating system and for all WiFi connections set MAC address randomization.

For Windows 11 it is under Network & Internet -> WiFi right at the bottom -- "Random hardware addresses."

For Android it is on by default for WiFi connections -- check all of them you use, and it should be on.

I suspect IOS on Macs has a similar feature.

Unfortunately for most systems there is no similar setting for hardware connections (e.g. cabled.)

This didn't used to matter much in the world of IPv4 because MAC addresses do not travel beyond the local network.  They have to be unique within the local network domain (e.g. your WiFi access point or similar) because that's how the network builds the mapping table so it knows what IP address (for example) goes to what machine.  Since they never leave the local domain the only real value in the IPv4 universe was preventing some local actor from mapping recurring device presence in a given place.  It would take a great deal of effort to put together any sort of "coalition" between such locations to develop any sort of effective "profiling" capability.

Unfortunately in the IPv6 world this is no longer true. SLACC, which is what most IPv6 networks use for local devices, results in a globally-unique address that is specifically tied to your hardware and is visible anywhere on the Internet you connect to!

So now when you connect to any site on the Internet and are using IPv6 the other end has a globally-unique identifier for your specific device, and unless you can randomize the MAC address it uses you now have dropped a "breadcrumb" that identifies your specific machine.  You did not have to sign on, your browser didn't have to send a cookie or do anything else for this to occur.  The mere connection attempt is enough as that address always winds up in the other end's log data.

Of course with a mobile (e.g. phone) the carrier controls the assignment and can link it to your radio, your SIM card or whatever else they wish.  Again this becomes a globally-unique identifier and in that case there's no way for you to get around it.

Mobile providers can and some do also inject what amount to "super cookies" you neither see or can control into all data streams that use the HTTP-style protocol stack, which is most of them incidentally.

In addition your mobile devices (including wearables - yes, that includes wireless headphones) have a Bluetooth MAC address that is globally unique and typically cannot be randomized.  If bluetooth is enabled that MAC address is visible to any device within 30' or so whenever the power to that device is on.  You have to balance the potential value of this being tracked by third parties to the value of whatever it provides to you.  The good news with regard to Bluetooth is that it is severely range-limited.

Do not kid yourself as to the lack of value in this information.  It is how many entities "geotrack" people and yes, its not only are all these MAC addresses unique they are tied to you and on mobile devices in particular it is essentially impossible in an IPv6 world to avoid being tracked this way because you have no control over addressing on the cellular network.

But when it comes to WiFi connections you can avoid it -- and should.  It has absolutely no value to you but may well have plenty of value to others, most of whom you'd probably rather it not.