You specifically asked about plasma cutters. Just upstream of your plasma cutter, you should absolutely install an M60.
Personally, I have an electric programable drain on the main compressor tank- which acts as the first line of water defense- every hour or so, it is supposed to open a valve at the bottom of the tank and drain the water for 30 or so seconds- all adjustable.
Secondly, I have a cheap, off the shelf water trap on the air line as it comes out of the compressor head.
just something like this, with a clear cup, so you can see when it accumulates water.
1/2" Particulate filter water trap seperator moisture Compressed Air Compressor - - Amazon.com
Then, in several places on the air line, as it runs thru the shop, I have valves at the lowest point that I manually open, and drain water from the lines.
There are a variety of ways to lay out air lines, but all generally have drain valves.
Air Piping Layout
You really need all of this stuff.
And I live in an area where the general humidity/condensation problem is not that bad- in certain areas of the country, you will need even more than this, including a thousand dollar or so powered air dryer.
But for your plasma cutter, buy an M-60. Really. Its been proven to be a vast improvement, by thousands of users, over decades, and it increases tip life and improves cut quality.