[0]: https://grow.google/certificates/ux-design
I suggest going to the roots of design thinking with IDEO and the Design of Everyday Things, read about good patterns at the NNGroup, the Baymard institute or Don't Make me Think. Then learn about the most effective frameworks and tools for UX right now like the double diamond, interviews, surveys, data analysis, prototyping or user testing.
Certificates are generally only helpful for entry level positions and ensuring outsourced "expertise"