If I were you, I would stick with applying for senior or management positions if that's what you're looking to do ultimately. Are you interviewing or are you working on your resume?

If you have any long-term clients in your portfolio, maybe break those out as subsections within your resume under freelance/contract work. Instead of having many bullet points for freelancing, you have it broken out by company/project.

I'd suggest working on the proof of concept projects in your downtime with the language you're interested in working in. Unfortunately, I do not see many PHP jobs (that I'm interested in, at least). Still, I'm seeing many Go, Python, Ruby, Java, and .NET jobs, and you seem to have familiarity with most of those languages.

I think an excellent senior developer can understand the core concepts of what's going on in the application even if they're not an expert at writing the code, so I would lean on the fact that you bring prior experience with several different languages, and over many different industries. You'll be able to share pain points you've run into, best practices you've learned over the years, etc.

Best of luck in your job hunt; stay focused and keep your head up - don't devalue yourself!