Should I add supporting exercises? (L-Sit)

Hey Bwf,

My current strength goal is to be able to hold an L-Sit. I have been progressing for about 2 months and currently have a 15 second tuck hold (in sets of 4, total one minute per tutorial). This leads to the slightly broader question I have about adding supporting exercises when trying to get a specific goal. I feel like my progress is stagnating. I will usually add some leg raises or straight leg holds to help build core as well as compression work. So, when I'm trying to achieve a movement such as L-Sit should I add these type of supporting exercises? If so, which ones for L-Sit? If not, should I be experimenting with different levels of progression and sets/reps?

Thanks for reading guys.