Well it's not looking much better, but it is at least readable. On Vanced, the fonts are white.You don't think but you are not sure. Any chance you could test it with the original YouTube app? It's dark in the original YouTube app, it's dark in the modded YouTube app, it's themed with some other substratum theme as reported by @Zgadnijcie , so it's not looking very good for your subs theme.
Who, what to fix?!
Screenshots how to whitelist in AdAway are attached. Reboot to take in effect
There is also TeMeFI which is thorough and has a GUI.