Who cares if it's VSCodium-based?
There are exceptions. E.g. Theia actually does enough stuff differently that I think it warrants being its own thing. At least it did. Looks like they have jumped on the AI bandwagon too.
Maybe this is the same; I haven't looked at it in detail. But "we have an IDE! (don't tell them it's vscode)" feels a lot like "we have an app! (don't tell them its a webview)".