@Eohsi_ Iโd disagree, you are still kinda new to the gym so doing compound lifts would benefit you more than isolation movements due to it working multiple muscle groups at a time. This will allow you to build more muscle mass for now at a faster rate. Isolation work is still good tho.
@Eohsi_ Yeah itโs most likely because they havenโt recovered. Change ur split so you have at least 2 rest days and make sure in your split you arenโt training the same muscle group 2 days in a row etc