Seeking Advice on Building GTM Expertise and Portfolio

Hi everyone I am currently working as a Growth Marketing Manager at a B2B SaaS company and I have over 5+ years of experience in Performance Marketing, Content and Marketing Automation. Lately as part of my job, I got a project where I am actively working with Clay and Instantly. To further improve my expertise on GTME, I am look for a part time/ freelance gig. I am very flexible with the commercials as I am mostly doing this for learning purpose. Do you think it is the right approach, if not what else can I do to gain expertise and also build a portfolio of GTM projects. Would love to know what you guys think?