Well a few of the Informant missions are carp hard.
Particularly the ones where you have to assassinate X number of targets in 3 minutes.
Towards the end of the game I was just avoiding the Informant missions altogether. The Pickpocket, Eavesdropping and Interrogation missions are much easier. Make sure you go for those because the Informant missions are just carp. You have to do these other things for the Informants too where you have to collect X number of flags scattered around the city in a certain amount of time, and while the flags follow a general trail, it's still frustrating because sometimes you will walk right next to a flag and it won't register that you touched it and due to the auto jumping Altair will keep jumping and you'll have to turn around which carp you on the time limit.
Yeah. Just avoid the Informants. lmao