The standard for what you’re asking is UL 458. What makes this a standard for 12 volt and 24 volt, I really don’t understand. I googled the standard, but its a pay to see. Very expensive as in hundreds of dollars. There are many, many inverters that are not UL-458 compliant. There are also You Tube videos of inverters bursting into flames when operating at their :rated” power.
I do have three inverters, all UL 458 compliant. Why? Even though I don’t truly understand the convention, there are 300k+ electical fires a year in the US, so I am as safe as I can. Two of my inverters are SAMLEX’s. Each of these has a cheaper non- UL 458 compliant available, but opted to go with it.
When building a 12 volt system, you’re in the Wild West and get to do what you want. To put it into words, if you’re not using a UL 458 inverter, you need to be really careful in approaching max rating and especially if using it for extended times. If you hav a 2000 watt heap inverter and run a 100 watt TV off it, not an issue. If you expect it to run your 1200 watt microwave which draws closer to 2k watts, expect it at best to not work, and at worst to be dangerous.