So you should separate tech companies, from companies that use tech.

Tech companies really care about your tech skills (assuming that you do not want to go to the manage route), so age should not be an issue. However, skills might be an issue. I.e. if you spent your career in companies that use tech, you might not have deep specialization.

Companies that use tech, are easier, which tends to bring less experienced developers, which usually are younger and might create ageism.