Need help to relearn programming concepts and gain confidence.

I am working as a senior software engineer in a company for last 5 years. I have total 10 years of experience. Initial 5 years I have worked on Microsoft technologies like ASP.NET MVC, C# Razor pages and Angular with MS SQL. Later since last 4 years I am working on MERN stack with typescript. Along with MERN I have worked with docker, kubernetes and Azure cloud. Since last two years, along with development, I have given various tasks of supporting team members when they are stuck, assigned support tasks rather then proper development tasks. Sometimes I am doing something in Azure, Sometimes I am writing small fix in React, Sometimes looking into mongodb issue etc. Initially it felt good for a year, like learning new things but now it feels that I am loosing my edge in development and feel stuck. I have spoekn with my PM but no change.

Now planning to move out and join another company. As I am not confident about my technical skills, I have started preparing like writing some code, watching YouTube vids etc but I feel it may not be enough if I say I have 10 years of experience.

How do I pick up things faster so I can start appearing in Interviews?

TLDR: Technical guy with 10 years of experience stuck in non developmental tasks and need to learn things again. How to pick up faster?