Head gasket or crack head

I got my truck to a mechanic because it was leaking coolant from the reservoir lid and it was misfiring. I thought it was the head gasket their diagnose was water pump failure and 2 out 4 injector on the passenger side they suggested to replace all four and the thermostat and the water pump. 46 km later our truck overheated so much we were stuck on the side of the road. we call and got back to a different mechanic they thought it was a air pocket they tried to fix it nothing. better now I’m waiting for the other shop to open and I’m pretty sure it the head gasket since we already have an EGR bypass. did the mechanic made a mistake? did the rack of changing the injector blew our head gasket? what is going on now? we have a motor leak and a massive prestige leak and an overheating truck probably due to pressure free. help please.