what's too long before querying about a submission?

After putting together a submission for a magazine when their new call for submissions landed in my email inbox this morning, I discovered that they still have my submission from September 2020. If they're actively soliciting new work, they've obviously got staff (not sure everyone does, in COVID times). So is it time to ask what happened to my sub? That's the oldest, but I have two others from January and February 2021, both at prestigious magazines that have published me before! Doesn't make me feel particularly cherished that they're taking this long. I've decided to keep waiting on those, and ask about the September one. So hard deciding where to send things, whether to do simultaneous (I didn't for the February one, since they frown on it), how long to wait. This is also an exceptional year. I get that.