What is the definition of a remote worker for the Thailand Elite Easy Access Visa, and can I work for a foreign company while living in Thailand?

It should be based on where you’re employed, not where you’re working. Does that make sense?

As stated above, it is not legal to work in any capacity while living in Thailand if you do not have a work permit. Even volunteering (when there was such an option) required a work permit. It doesn't matter where you are paid or where your customers are located. If you are located in Thailand and working, you need a work permit.

Having said that, no one will know what you do in the privacy of your own home or where your money comes from. Unless you get on someone's bad side or there is a dramatic shift in how the Thai government deals with the digital nomad situation, you will probably live consequence free... but just know, you are not in compliance with the conditions of your visa or Thai law if you engage in work activities without a work permit.

Short version, you will probably be fine... but you won't be legal.

Be aware it has nothing to do with a official Thailand Embassy.

But a privat compagny, which try to decieve people.

Just be aware that ThaiEmbassy.com is a visa agent site. Unfortunately many people are conned into believing it's an official Thai government website. It's not. And they publish a lot of misleading information

The only visa that legally allows you to work remotely in Thailand is the LTR visa.

There are many people working remotely on other visa types, they just don't advertise the fact since the legality of doing remote work in Thailand without a work permit is a grey area as the laws were written before the internet.