New to Pathfinder 2e, are enemies supposed to hit that hard?

I just recently started getting PF2E, and joined a group of friends [group of 4] playing an official campaign. The current situation is that we're all exploring a dungeon, and throughout the dungeons we fight many undead. Now currently, we are only lvl 4. The highest AC of our group is a champion with 24 AC (with buffs and a shield) , we have encountered many enemies along the way that seems to always hits us. One of such enemies was a named ghoul, that wasn't even a boss fight. This one combat was extremely hard and we had to switch out the front lines constantly. When the DM revealed that this ghoul had a +15 to hit, everyone was just shocked. No one else had an AC as high as the champion, and it was extremely easy for this ghoul to crit and cut down any summons that we brought in.

From a 5e perspective, a +15 to hit in an encounter with a ghoul that wasn't even a dungeon boss, at lvl 4. I don't know how crazy PF2E is going to get but i'm here asking genuinely :C.