Unless you go dirt I'm going to say you will likely have the same issues. Pythium is not temp dependant. It attacks roots at any opportunity. Higher temps only speed up the metabolic and reproductive rates. There is a reason you kept getting it and without finding you will likely have the same issue no matter what type of hydro you do
The reason that you have less chance with dirt is that the dirt is more like a buffer.
With hydro everything is very direct.
So with hydro you have to make sure that all your circumstances are ok.
For example there are less beneficial bacteria in just water. There is also nothing that the bacteria can hold on to. Just the water and the roots. One of the reasons for fungi like pythium.
Temperature differences can be a cause: When you change your reservoir and the new water is colder then the water you had before. With soil, the soil will keep the same temperature much better.
Lack of oxygen can also be a cause of phytium. Now there is always plenty of DO in your water with almost any hydro system. But the question is: does the water inside the rootball gets refreshed as well? Stagnant water inside a rootball can be a problem. Plenty of DO rich water around the rootball, but inside the rootball it is dead. With soil there is plenty of O in gaseous state (if your are not drowning your roots of course)
Pythium does also occur in soil, cocos, rockwool, etc.
A reason for pythium can be that your EC is too high. Your roots get less defensible.
Also a high temperature of your roots and a low temperature of your plants can help getting pythium infection.
When your root temperature is for example 23 degrees and your plant temperature is lower, this also can be a cause for pythium. In the night a lot of growers have their room temperature below the temperature of their medium.
(I think this is why a lot of people with chillers perhaps have less pythium: Their root temperature is never higher then their room temperature. Many of them think that pythium occurs just by the simple fact that it gets active only above a certain temperature. But Pythium can occur by any temperature, although when you get above 30 degrees it will occur way faster)
I do realize that in nature this situation does also occur in cold nights, but what I am describing is how commercial growers try to avoid pythium.
It is almost never 1 reason: It are several circumstances together. Some spores that were already in your water. Some temperature problems, killing too many beneficial bacteria with H2O2, biofilm in your tubes, lack of oxygen, your EC a bit high, a little bit of this and a little bit of that.