Leetcode tasks are quite fast. They must be a requirement.

They check the way you think, first of all.

But there is high competition. The first technical interview is easy. However, if you don't practice Leetcode tasks in your real life (which is far from common for QA people, unlike developers), you might waste your time on overly detailed preparation specifically for this company, instead of doing real-world practice tasks. I really don't recommend QAs tackle very complicated Leetcode tasks – you'll likely develop complexes about not being able to prepare everything in two weeks. Leetcode tasks require long-term preparation.

Easy LeetCode tasks: write asserts.