Not white.
If footballers want to 'take the knee', let them. They're well-meaning. I'm not keen on the gesture myself though as to me, racism creates a 'them and us' division, and kneeling down creates a 'young and old' division. I don't really like division.
Not an issue amongst a group of elite athletes who can easily get up again, but if you roll out that gesture into the wider population, there are a lot of people (me included) who would struggle to get up again! I'd prefer something like bowing your head, as that's a bit more inclusive of those of us with dodgy joints.
(The idea of linking arms as suggested above is nice, but not very Covid-safe.)
I get that the origins of the gesture come from NFL and the reason was to show respect without standing, but in the context of BLM, the gesture makes me a bit uncomfortable. It makes me think of Derek Chauvin kneeling on George Floyd's neck, and I just don't know why you'd want to make a gesture evocative of that. Personally, I'd find a better protest to be doing something as far removed from that as possible - Chauvin was kneeling, so standing. Standing with your head bowed, maybe.
In short, I'm very anti-racism, but the gesture puzzles me a bit. I guess I'd just rather see evidence of people not being racist in their everyday lives - such as actually calling out others for making racist comments - than see people kneeling at events.