In general I am all about the right to repair and have done some DIY audio stuff as well, but what is the point of a "repairability score" for a product like this? Feels like giving a "soup eating score" to a fork.
A "repairability score" makes sense for a lot of products. If I buy a desktop PC I would be able to swap industry standard parts in and out. If I buy a car I would generally expect to at least do some standard maintenance on it like replacing the air filter, and I think it's reasonable to expect to install replacement blades on my lawn mower.
I'm not sure it makes sense to apply that to a tightly integrated non-portable bespoke product like this. What am I going to do, open up a HomePod and throw some bigger tweeters in there? My cordless electric razor isn't particularly hackable or repairable either, but that's okay. I don't really expect to be able to throw a third-party foil cutter thingy into there.
Part of the "price" we pay for small and tightly integrated products like this is that everything is custom. The onboard DSP is tailored to these specific drivers in this specific arrangement and so on. If I wanted something to hack I'd design my own boombox kit or buy one from PartsExpress as a starting point. (For the record that's precisely what I did)