Doesnt the process of making the rosin already decarb it?
Nah, it takes about 30 minutes @ 250F to decarb.
For pressing hash, try using a small amount of pressure until the hash turns into a brick or patty first, then just ease into it until it starts juicing, not gonna need near as much pressure as flower. What press are you using? The coffee filters are probably giving you some trouble. If it's bursting at the very end perhaps you are just applying too much pressure. You could also double bag it, would steal a little yield, but less than dealing with a blowout.