Silvia V3 - Water out of group head and steamer simultaneously when pressing coffee switch

Hello! I recently bought a used Rancilio Silvia V3 for cheap as a fun DIY project. It was clearly in a bad shape, so I did some descaling, installed a new group head gasket and cleaned the shower head. I also installed a completely new steam wand, as it didn't work properly according to the seller.

However, when trying to do a shot of espresso by pressing the coffee switch, after the boiler has heated up, water is also coming out from the steam wand. The water pressure from the group head is also a bit low as well, I would say.

I have tried to do a lot of Google searches regarding the issue, but I can't seem to find the solution. The closest I have come to find a solution is either opening the boiler and cleaning it and/or buying a new steam thermostat for the machine.

Anyone who have had a similar issue before and could help me with a fix?