GCP VPC Peering auto-mode

Question

I have two GCP projects which have their own VPC (created in auto-mode) and I would like to create a VPC peering connection between them in order for the compute instances in both VPCs to communicate with each other.

But since the VPCs were created in auto-mode, the subnets of both networks are using the same predefined range of IP addresses meaning that I cannot connect the VPCs together because the IP ranges are overlapping.

In the two VPCs, my compute instances are in the "same" subnet and converting the subnet mode (from auto to custom) could allow me to change the IP range of those subnets. But the new IP CIDR range needs to be a superset of the current IP CIDR range and the IP ranges will still be overlapping.

What could be a solution here ?

Note that I do not need to have a subnet created in each region since I am only using 1 or 2 subnets as of now.