The limitation that you can have only 32 devices wired daisy-chained on one link is a limitation of RS485 networking standard.
A DMX splitter allows you to connect more devices on the same system. Theoretically if you have enough many splitters there is no limitation how many devices you can have connected on the system.

The DMX-512 standard specifies that there are maximum 512 different control addresses. A single device can use one or more addresses.
There is no limitation how many devices you can have assigned a single address. You can have one, two or more devices set to same address and they all work nicely, but they will all get the same controlling data (means if you have three dimmers set to same address, they all have practically the same output (within equipment tolerances of course) controlled by same slider on lighting board).

So you can have up to 512 dimmer channels that can be controller separately. It is technically possible to connect more than 512 dimmer channels to one DMX-512 link if you can accept that some of the dimmer channels always get the same control data, meaning they can't be separately controlled.