Do you get these dictionary words on other apps? Because I haven’t seen them on the C2, as far as I know there is no Text Prediction Engine on C2 at the moment. ([C2] Predictive Text Input on SailfishOS 5.0.0 missing? where you can find a community solution with installing an app from CHUM.
And this could help with the Certificate? Adding my own root certificate to sailfish os - #5 by leon