I changed my Engies to have 1, 2, and 3 visible because I can't see the little tech lines zoomed out, but maybe that is also too much.
I'm looking at your screenshots and not totally a fan, but I do agree that with the default icons finding that T2 engy is too hard. Perhaps use the spanner symbol, then make it a double/triple spanner for T2/T3 engies? But the 1/2/3 icon is good enough to also make an option, if you are willing to make a few variants.