Personally, changing (some of the) vocalists don't make it no Star One for me. But I would've preferred a more "band-like" approach that the first two had, instead of the Ayreon approach. But in the end good music is good music. I like him returning to the singer per song approach for this one, hopefully the songs make the singers shine and let them use their abilities.
And I can't blame Arjen, he is probably at the peak of his popularity, his latest releases have done very well. So he now probably has the ability to get some of his favourite singers or big(ger) names easier, especially in the non-touring times of covid.
Also, wasn't The Source initially going to be a Star One album?