The i18n has apparently progressed (can't speak to it, though; we're still using ngx-translate, without which Angular life would have gone to Hard Mode) but the testing (and also debugging runtime errors) story is still the utter trash fire that it's always been.
"Unit" or "component" testing works, but there is tons of boilerplate required in real-world situations, which will often only become obvious after you try to run your tests, so it is tedious to write.
Protractor (the previous Angular-sanctioned E2E test framework) really died with AngularJS, so it's been a pretty unworkable and high-maintenance mess this whole time, and they only just now finally came to terms with this and killed it. (Also didn't replace it.)
P.S.:
From grievous and traumatic personal experience: Don't use Cypress. Use Playwright[1]. Cypress was great in 2017 of you were coming from Selenium/Protractor. But Playwright in 2021 is to Cypress what Cypress was to
Selenium in 2017.
[1] https://playwright.dev