I have different wattmeters and different smart plugs with wattmeter function.
I m so confused lately because all of them shows different values

This is the one which i hae been using for 5 years. It work well.
https://www.banggood.com/Bakeey-16A-Plug-in-Digital-Wattmeter-LCD-Display-Power-Meter-Electricity-Usage-Socket-Adapter-Electric-Consumption-Monitor-EU-Plug-p-1643668.html?rmmds=myorder&cur_warehouse=CN&ID=530036

This is the new one i have bought latelt. And this is the startf of the problem. It shows +150W than the first one around 1600W/hour.
https://www.banggood.com/EU-Plug-Intelligent-AC-Power-Meter-Wattmeter-Socket-Billing-Socket-Power-Monitor-p-1815410.html?cur_warehouse=CN&rmmds=search

For example:
First one shows 1650W, second one shows 1800W

This is the best smart plug i have used. It shows +20W than the first one. But the warranty is so bad. I have no warranty for my country.
https://www.banggood.com/Broadlink-Wifi-Smart-Plug-SP3S-Power-Meter-Monitor-16A-Timer-Socket-Outlet-Remote-Wireless-Control-p-1249628.html?cur_warehouse=CN&ID=43101&rmmds=search

This is the worse smart plug i have used. It shows +75W than the first one. It sometimes can be out of order after electrcity is gone and come back. But the warranty is perfect, they send the new one.
https://www.swapp.com.tr/tr/urun/s-link-swapp-sl-01-16-amper-akilli-priz-wifi-tuya-destekli

I have also several smart plugs which all of them shows different values. I have no any idea which one shows correct values.
There is no any difference if i use lower than 700W, all wattmeters shows the real usage.
Help me to choose a perfect wattmeter.