It sounds like you have the experience needed, it’s just a matter of getting your name out there. If you’re looking for a full-time position, I’d recommend creating a website with client testimonials and key projects, describing your role and overall outcome as accurately as possible.
It’s important to keep connecting with others and nurturing the relationships you’ve built over the years working on so many different projects. Talk to your colleagues, young and old, about the roles they hold. This will likely give you some direction.
You don’t always have to mention your age if you think it might be a factor. However, things like a website or a detailed, up-to-date resume are very important and need to be tailored depending on the role you’re applying for. Not so much your LinkedIn, but it’s important to be active there and share your work too.
Aside from speaking to recruiters and reaching out to candidates via applications, I recommend looking into networking groups in your industry – perhaps you could join a music week. Go to events and meet as many people as you can. Check out events like The Dots or It’s Nice That’s monthly ‘Nice Tuesdays’ event series.
