You want to display $\frac{n(n+1)}{2}$ values of a symmetric $n \times n$ matrix, where $n=26$, which means you have 351 values.
It doesn't make too much sense to display all those numeric values. After all you want to display them to a human being, which is unlikely able to oversee all these values if displayed as numbers.
Then as you say, the values have different units and ranges. that means there's no automatic way of finding the "good" range.
I suggest running the system for a while, disturbing it, gathering some rough estimates of where the values are and to what peaks they can rise.
With these values you can provide a rough estimate of "good" and "bad", somewhat fuzzy if you will.
Back to the original problem: displaying all those values. A numerical display is out of the question. And that precision isn't even desired, so why not map the values to colors and display each value as a pixel? Make good green and the red bad. Now the job looks a lot simpler: display some 351 pixels1. It's easy to see when some pixels go red if something goes wrong and what other pixels go "hot" at the same moment. It's also easy to see if some values are generally uncertain, constantly staying in the orange color.
Depending on your needs you can expand that debug facility further, allowing the user to only display a subset of the matrix. Or allow closer inspection, displaying the true values behind the colors and/or plot them to see how they change to the "bad" state.
1of course you can display these values as large as you want. I'd start with a a 10x10px box for each number, resulting in a 260x260px box, which should be big enough to see clearly, yet small enough to add other debugging/observation tools around it.