How do I remove hmlt000**** network and ensure safety on my Mac?

It is some device on your network that is advertising its services. Your Mac thinks it is a PC, but it could just be a device that uses the same networking services as a Windows PC.

Usually, those numbers are the network Media Access Control (MAC) address, but yours has an extra digit.

Some printers that have media card slots to print directly from the camera cards will share that out to the network.

Just because it appears in the Network browser doesn’t mean it has any access to your Mac. It’s just sitting on your network telling anyone who will listen that it has some service available to connect with. Your Mac is just telling you it exists if you want to avail yourself of its services.

It says it’s a PC, go to settings>your name and scroll down to were you devices are, if it is there then that is your security risk, and you click on it and click remove for account and go to Change you password and change it.

If not then it should be ok.