I found a small black/grey bug on a couple of my plants. After some research I believe they're springtails. They are very small and will jump. I haven't seen them on my plant's leaves, only in the soil. I understand they aren't harmful to plants. Is there anything else this bug could be? If not then I don't see a need to isolate the plants... right? I included a picture I took of the bug, but they're so small my camera can't focus on them well.

bonus question: I read that springtails tend to be seen in plants that are overwatered. I found them in my hoya pubicalyx and DS-70. They both seem to be doing very well. These two plants never pass the taco method or have their leaves wrinkle. Should I wait to water them next until I do notice one of these things? I don't want to damage the roots by underwatering, or have their new growth stop because I'm letting the soil stay dry too long.

Thank you!