I worked at a CyberSecurity company for 12 years where they had a well defined career path for QA Engineers from Junior - Principal and with a technical and management path too and presumed it was the norm.
Then my following two roles have literally had “tester” and “test manager”, so I’ve recently been working on building a career path with clear distinctions between tester, senior tester, test lead and Test Manager.
Really the main difference between Tester and Senior Tester would be the broadness of influence and areas where they may be an SME. They may also have more technical knowledge of tools and automation but I guess it comes down to expertise and trust mainly. seniors would also be expected to coach/mentor more junior members
With the Lead position, it may be the first step on the management/leadership path so having some level of people leadership and project management skills alongside testing
Happy to discuss what I’m building further offline at some point if you wish…