I used the term rougelite instead of rougelike. This is explicitly to distinguish it from games like rouge and nethack. FTL has some elements of these games, procedurally generated levels, permadeath, exploration, PvE, RPG elements, crushing difficulty, but not others. Thus rougelite.
Anyways trying to define what qualifies what a "rougelike" is has started countless semantic slapfights (which is why I tried to use the cop-out word rougelite). Please consult a rougelike alignment chart to know where you stand in the great holy war over the definition of the word "rougelike" [1]. Nowadays most gamers think of indie games like dead cells, hades, enter the dungeon, darkest dungeon, crypt of the necrodancer, and ftl when they think "rougelike" and those games are all tagged with "rougelike" on steam and twitch.