Yup, your prediction was correct! Alex Albon did fill the spot as he signed the deal for Williams! To be honest, I am also happy for Albon for having the opportunity to race in a Williams car. His role in Redbull was similar as of Valterri's role in Mercedes. I do hope that he gets the spotlight he deserves in Williams, do an inferior car compared to Redbull.
I have mixed feelings (especially as a RBR fan).
I am happy for him, that he will actually race again, even though in a car much weaker than the RBR car he had before; but maybe the Williams different aerodynamics will help him adapt better to the car than he did with at RBR. It looks like the RBR car is somewhere/somewhat different than the others.
On the other hand, he may know some "trade secrets" of RBR that will now be passed Williams and from there to Mercedes. And this is not nice, especially as Lewis was one of those ruining Alex' chances to running more seasons at RBR.
And I don't feel that he had the same role as Valtteri. He may have had that if he would have been more constantly "there". But somehow that didn't happen. I know that in some cases it was bad luck too and he may have been deserving more, but unfortunately for him, Sergio was more constant and more appealing (and he also does until now, on average, better job). Also I feel like RBR is somewhat more lax than Mercedes with the team rules.