In my opinion
You did right, stick to dot3/4/5.1 fluid
Because
Your brake system is not sufficiently sealed up tight from the environment to support dot5 in its intended application
The master is vented to open air where water splashing can introduce serious moisture
And the wheel pistons aren’t super great at being sealed tight either, one layer of protection like mechanical screw threads or a broken boot let’s moisture into the system
So using dot3 technology and replacing the fluid regularly is the way to go (2-3 years total flush is what I aim for)
A dot5 system is meant to be super sealed tight
And no water ever gets in
It is not vented to atmosphere
And the fluid goes a longer time between changes

If you get water in dot5 the wheel cylinders will rust and pit on the bottom inside and the roughness cuts the piston cup seal and then it weeps brake fluid
This problem also happens when you don’t flush the dot3 and it’s ability to hold water is exceeded
-s