The driver is just one part. When the drivers are installed other files and registry entries get written and tied to programs and APIs. If those are there it can cause issue.
I have almost never seen a multiple card setup with different GPU brands. Normally someone will have two or three of the same brand GPUs. The only reason to do this is if they are trying to get more than the maximum monitors. Say they want 6 monitors having two will allow that.
But again I have never seen someone throw a GT1030 and a RX550 into the same system. They would normally use two GT 1030s as there will be less potential issues with drivers.