Your team is using Linux instances on Google Cloud.

Attach a public IP to the instances and allow incoming connections from the internet on port 22 for SSH.

Use a third party tool to provide remote access to the instances.

Use the gcloud compute ssh command with the --tunnel-through-iap flag. Allow ingress traffic from the IP range 35.235.240.0/20 on port 22.

Create a bastion host with public internet access. Create the SSH tunnel to the instance through the bastion host.