Just a side note - I would caution about directing non-Black folks to spaces like # BlackMastodon and @ blackfedi, just because those spaces might not be intentioned for non-Black people to look at, directing us there might be encouraging our participation in spaces where it's not necessarily invited or wanted, etc. Great spaces to direct Black folks to if they're looking to build a community for themselves on fedi, but I would just say it's best for non-Black people to not look/participate unless the space is specifically inviting that.

The other thing about the "just listen more to more Black people" discourse is that while it may fix representational issues of whom you're choosing to listen to, it won't help if there's no intention to work on racial biases or challenge one's own racist behaviors - so I would even implore that type of introspective work. Connected to that would be, even if a white person starts doing these things and working on this practice, that work of interrogating your own biases/behaviors never stops. I feel that white people (especially on fedi) often need reminding that just because you're doing X, Y, Z, etc. doesn't mean that you're done working on your own racism or that your reasons for doing X, Y, Z, etc. are all genuine.

You might also want to mention how having some marginalized identity even as a white person doesn't excuse you from doing this work - there's a lot of harm done on fedi by people who use their own oppressed identities as a way to avert accountability for being racist. In your piece, you already mentioned that supporting Black people and fighting anti-Blackness means supporting all Black people - you could make that understanding of how anti-Blackness is interconnected/intertwined with other oppressions more apparent by appealing to white people who might consider themselves staunch advocates for other communities but refuse to confront racism.

This is kind of a mess of different comments but those are just my raw thoughts after reading what you wrote.