no reason you cant jot down ideas for one game on a notebook or google doc or something while working on a different game. hell, you could even do 2 at once if you feel your up to the task. i know that there are some xxx game devs who get shit done on multiple projects at once, but im sure that takes up a lot of time/effort and creates a lot of stress for the dev. just dont overwork yourself or spit out a game thats less than what you want it to be
i used to juggle projects so i could keep working when i got bored of a particular type of task, burnout means i cant though, i have to choose
i made a top down prototype this week but im having trouble conceptualising the actual world map (even though its just a basic cabin in the woods with a few dungeons
i wanna make lewd slay the spire but rpgmaker keeps getting in the way, and i cant do it in game maker cause i lose live2d
i also have a live2d model made for my next rpg, but the plot isnt strong enough yet so i got stuck there too
so yeah, i need to decide what to make properly