They are the same problems you see on Tactics Trainer. Please post an example of a killer 100-rated problem.
Your Puzzle Rush score says your highest level solved is around 1200. In tactics trainer, you would solve those easily. It is only the time factor which makes them seem difficult.
First of all, how come there are tactics puzzles rated as low as 100 elo on the site? A few of them were harder than the ones rated 2000+ I've seen on tactics trainer.
Second, the difficulty is relatively easy with mates-in-one, hanging pieces, recaptures, obvious knight forks and so on and at some point skyrockets to counterintuitive sacrifices, complicated sequences involving calculation of long lines (4-5 moves+). It happens in an instant and there's nothing in between.
Finally, the three strikes ruin my runs when I'm at my A game, while time gets the best of me before long when I'm doing badly. It's the same problem with tactics trainer, the clock dares you to make a move which results in more mistakes than usual. I know what you're saying, "don't move until you see it", but there are some problems where the situation is so counter-intuitive you don't really have a choice. Did I mention you can't really see the solution when you get something wrong, so if it's some pattern you don't know, you don't even get to learn it?
My proposed change? A time penalty of 15-30 (+-, don't know what a good value could be) seconds per mistake. The time one wastes to arrive at a wrong solution, losing the point, is also a penalty so things should be fine. I understand the purpose of strikes, to make it so people can't just breeze through with the first checks and captures they see, hoping luck will be on their side, but the current system is way too stressful, let alone having only 3 strikes.