How to play as Israel in GFM/other mods?

Pretty much the title. I know that in Vanilla its cores spawn with the Balfour declaration event (that can be launched by the UK I think?) but browing around this sub I see a couple Israel playthroughs, on one of them the OP mentioned using GFM without more precisions, on another I see GFM with Fantasy Formables on... Tried both at the start date of both 1830 and 1836 and I can't find any of its cores, any decision to release it (checked for Ottomans and UK).
Am missing something or doing something wrong? Is it just not plain possible to start early game with Israel?