Yeah, this is actually a pretty common issue, and you’re already on the right track. I found a very helpful explanation here https://hnmag.ca/choosing-and-maintaining-trap-primers-for-your-plumbing-system/ it breaks everything down in a simple and practical way.
Basically, what you’re describing often happens when the water inside the drain trap dries out, which removes the barrier that normally blocks sewer gases. That’s exactly why you start noticing bad smells. The solution in many systems is something called a trap primer — it’s a small device that automatically adds water to the trap so it doesn’t dry out, especially in drains that aren’t used often (like basement ones). What I liked about that article is that it doesn’t just explain what it is, but also goes into different types, how to choose one, and even how to maintain it properly.
From personal experience, I had almost the same issue in my garage drain. Turned out the primer wasn’t working properly, so the trap kept drying out. After fixing it, the smell disappeared completely. So yeah, definitely worth checking whether your system has one installed and if it’s functioning.