@DataMeister, there is an easy way to restrict access to certain APs or a frequency band for a specific device (MAC address): just create a second SSID per AP and/or frequency band for exclusive use by the device you want restrict access for.

This is the usual method to restrict access and it even works for those devices which try to circumvent a MAC filter by simply changing their MAC address.

DataMeister wrote

I have a Wifi printer that for some reason wants to change it's access point from the closest to an AP almost too far away and then ends up printing extra slow or sometimes showing offline when people try to print to it.

Obviously your WiFi printer has its own idea what AP to connect to and this is the reason why a MAC filter on an AP won't help here. There is no way in the 802.11 protocol to tell a device to not use SSID xy, but use another AP's same SSID xy instead. The SSID (to be precise: the ESSID) is a name for an Extended Service Set (hence its name ESSID) and it names the whole Service Set formed by all APs using this same ESSID. This is intentional and it's the reason your WiFi printer can select between two or more APs if the printer uses this ESSID.

802.11k roaming could help if the WiFi printer would support it (unlikely, since it isn't a mobile device which is moving between APs), but even 802.11k will use the device's RSSI detected by an AP, not a MAC filter, so in the end it could cause the WiFi printer to connect to the same AP to which it is connecting now. The ultimate decision is still made by your WiFi printer in case of an ESS.

So, what's possible is to force a device to connect to a specific AP by having this AP offer the ESSID the device is looking for. You don't need to create such an ESSID for each device, but only for the AP(s) to be used by those devices.