There are active discussions in the
https://cdk.dev/ Slack channel #terraform-cdk about building community-driven forks of the existing Hashicorp/IBM CDKTF repositories. A number of developers who work at organizations that are heavily reliant on CDKTF have offered to pitch in.
There is currently a live proof of concept fork of the main cdktf repository that one developer made:
https://github.com/TerraConstructs/terraform-cdk
And one Open Tofu developer said he and some other Open Tofu developers would be happy to collaborate with that community-driven effort to keep CDKTF alive:
"The OpenTofu maintainers are happy to collaborate with that project once it's up and running, but we will not be directly involved."
https://github.com/opentofu/opentofu/issues/3585