I have several Fibaro Smart Plugs (Z-Wave) in use, and I’m satisfied with them and the response to power changes is very good. But you can also adjust it. It’s also possible to include or exclude the self-consumption.
There are similar small smart plugs available from other manufacturers, such as NEO Coolcam (Z-Wave) or Shelly (WiFi), but I have no experience with them.
By the way, the power consumption of the Fibaro Smart Plug is according to the manual with max 1.6 W higher than that of the Shelly Plug S (< 1 W, according to the manual).
Another point to keep in mind is if the smart plug is designed to handle the power of the device.