Acmen5030 appearing in shared computer tab on mac
Your Mac is just letting you know another device on the network is advertising some sort of SMB share. It could be a printer with a card reader, it could be a legitimate PC sharing a printer or a folder on the disk, or it could be some sort of appliance or internet of things device.

If you log in to your router, you can see each other device and power them off one by one. Once you know what's causing the "mystery" share - you can either investigate limiting it's configuration or removing it from the network.

It's not a security risk or a virus on your Mac.