I definitely own it since it was an "extra duty" project and they never paid for it, nor claimed it, just used it in the early stages that's all.

Thank you for your feedback and I would love your take on something, does it make sense to try and do that blog series to for example build a reputation for an agency or a company?

Like we at ACME changed X on Y because 123 and so on.

Or focus this on my personal branding instead?

Just focus this on your personal brand.

You can still relate it to concerns/business requirements or processes that agencies might have, which you considered and factored in when you made design decisions about the code, architecture, or processes. But since this is more of a project that you built on your own and one that you own, it makes more sense to me that you'd present this as "I changed X on Y because 123" and so on.

I meant trying to use it to produce content to kick start my own agency, even if it's just me in the beginning, to try and get some reputation or credibility.

Oh, sure. You might be getting ahead of yourself with worrying about that at this stage, but maybe eventually.

Do you think i can get it in the spotlight somehow? Like I said, I want fail forward so I would want as much feedback on the code itself as I go.