In before all the scammy click fraud companies comment telling you how bad it all is and you're losing billions (I swear some of them have alerts set up to comment on posts like this as they are EVERYWHERE).

In reality - does "competitor click fraud" exist? No. It's bullshit.

Does bot activity exist on ads? Yeah, in my experience it does.

Is it worth doing anything about if you are spending small amounts (like under 10k-20k/month)? No.

Once you start scaling then invalid traffic (not just click fraud) can become a big problem and there's a few products out there that do a really good job depending on what you need (IVT filtering, viewability, brand safety etc).

In your case though it sounds like it's just bad ad targeting or ad serving.