Early adopters are the early users. They come on board because they are looking for a solution to some challenge and your product seems to hold potential in that regard.
They are not beta testers.
A beta tester is someone you pay to evaluate your product, use it, and give feedback on bugs therein.
A beta user could also be a friend, acquaintance, or friend of a friend doing you favor using your product.
Beta testers are anxious to test your product to the extent that you are paying them. Or, beta users will be willing to test your product to return a favor or barter for a future favor.
On the other hand, an early adopter is someone who believes that your product will help to solve a problem or meet a need and who you believe has a reasonable prospect of deriving value from your product. If they are evaluating your product they may not have paid for it yet but the expectation is that they will pay if they achieve a satisfactory outcome in a given period of time that is mutually agreed to.
Early adopters are anxious to see if your product will produce a better result than the existing alternatives that are available to them. They are not anxious to “test” your product.
Typically, early adopters will live with some bugs in your product, as long as it meets their core requirement or as long as they see you are gearing up to go there.
Both early adopters and beta testers have their own place in your product building process, You only need to know which one you need and in what context.