I wouldnt be so sure about that, Merc so far seem to have the most reliabilty issues of all the front runners, they cant afford to push their engines too much especially in race...
Lewis had issues with his PU, that is correct. On the other side, Nico only suffered in Monaco due to issues with getting heat in the tyres. Talk about other issues from Toto is just a part of their pace masking scheme, before FIA alters the rules again against their advantage.
What? Ferrari is far worse than merc in terms of engine reliability.
Well they managed to fix their issues, but at heavy price - they have only four more tokens to spend for the rest of the season, if I calculated that right (3 for Russia and 3 for Canada with only 9 left after winter). Mercedes still has 11 tokens to use.