Who said end-to-end tests for the web have to focus solely on the UI? Nico Domino shows a great example of leveraging Playwright features to support such tests with API calls.
If you work on a legacy test framework or your tests are not performing well enough, Lewis Prescott gives a few good pieces of advice on how to do the test refactoring.
Additionally, Chris Enitan explains that it may also help to Build tests as modules.
Whether you're already a tester or just thinking of starting a career in testing, you may want to read Nicola Lindgren's article explaining if it's worth learning test automation.