When involving Spring:
If you want to use Spring test framework features in your tests like for example @MockBean, then you have to use @ExtendWith(SpringExtension.class). It replaces the deprecated JUnit4 @RunWith(SpringJUnit4ClassRunner.class)
When NOT involving Spring:
If you just want to involve Mockito and don’t have to involve Spring, for example, when you just want to use the @Mock / @InjectMocks annotations, then you want to use @ExtendWith(MockitoExtension.class), as it doesn’t load in a bunch of unneeded Spring stuff. It replaces the deprecated JUnit4 @RunWith(MockitoJUnitRunner.class).
To answer your question:
Yes you can just use @ExtendWith(SpringExtension.class), but if you’re not involving Spring test framework features in your tests, then you probably want to just use @ExtendWith(MockitoExtension.class).