The default one on Samsung will let you select multiple languages under "Suggest text predictions". Not sure if that's a clone of the default Google one, but I had so far assumed so. Seems to switch decently between Dutch and English, for me.
Yeah. Though decently is not the same as excellently.
Written on a SwiftKey keyboard used to write English, Swedish, Danish and Icelandic with minimal issues.
Though to be fair, I think the stock keyboard is probably almost as good these days and that the difference is that my SwiftKey keyboard has been trained on my writing for several years.
Though I have no idea more than that I quickly get annoyed when I try to type on the stock one.