The question you have to ask yourself is if you were worth the counter offer, why weren't they paying you that in the first place?

The second question is that if you do take the counter, now that you've received a 20% increase, what are your next few annual increases going to look like? Will they be normal or will they cut back and say "well, we did give you that nice bump in 2023...".

My dad was a senior exec for a Fortune 500 company for decades. He always used to say that any employee that accepted a counter offer would be put on a dead end track because he knew they were a "flight risk". Couldn't trust them with "critical" projects because they couldn't be 100% trusted. While the working world now is very, very different than when he worked it's something that still sticks with me.