How get value from field using Selenium java

I try to get value (email adress) from page https://temp-mail.org/ , and put it to the string.

So my code is this:

maven dependencies:

<dependencies>
    <dependency>
        <groupId>org.seleniumhq.selenium</groupId>
        <artifactId>selenium-java</artifactId>
        <version>3.141.59</version>
    </dependency>

    <dependency>
        <groupId>io.github.bonigarcia</groupId>
        <artifactId>webdrivermanager</artifactId>
        <version>4.3.1</version>
    </dependency>

    <dependency>
        <groupId>org.testng</groupId>
        <artifactId>testng</artifactId>
        <version>6.8.8</version>
        <scope>test</scope>
    </dependency>
</dependencies>

I create Abstract page

public abstract class AbstractPage {
    protected WebDriver driver;

    protected AbstractPage(WebDriver driver) {
        this.driver = driver;
        PageFactory.initElements(driver, this);
    }
    protected abstract AbstractPage openPage(String url);
}

TempMailPage:

public class TempMailOrgPage extends AbstractPage {
    String regex = "^[A-Za-z0-9+_.-]+@(.+)$";
    Pattern pattern = Pattern.compile(regex);
    
    public TempMailOrgPage(WebDriver driver) {
        super(driver);
    }
    
    public TempMailOrgPage openPage(String url) {
        driver.get(url);
        driver.manage().window().maximize();
        return this;
    }
    @FindBy(xpath = "//input[@id='mail']")
    WebElement mailField;

    public TempMailOrgPage getAddress() {
        //new WebDriverWait(driver, 10).until(ExpectedConditions.textToBePresentInElement(mailField, regex));
        new WebDriverWait(driver, 10).until(ExpectedConditions.textMatches((By) mailField, pattern));
        System.out.println(mailField.getAttribute("value"));
        return this;
    }
}

and Test

public class MainTest {
    WebDriver driver;
    
    @BeforeMethod(alwaysRun = true)
    public void browserRun() {
        WebDriverManager.firefoxdriver().setup();
        driver = new FirefoxDriver();
    }
    @Test(description = "try get addresb")
    public void scenarioWithCopyingEmail()  {
        new TempMailOrgPage(this.driver)
                .openPage("https://temp-mail.org/")
                .getAddress();
    }
    
    @AfterMethod(alwaysRun = true)
    public void afterTestCompleted() {
        driver.quit();
        driver = null;
    }
}

And after test running I get error. I understand that a mistake in waiting then email address is generating.

And instead of a word "Loading" will be mail address. In this line I try to use pattern:

 new WebDriverWait(driver, 10).until(ExpectedConditions.textMatches((By) mailField, pattern));

What am I doing wrong with waiting?

P.s. using thread.sleep not a way.