Conditionally use resource with for_each

Terraform
1

I try to update from terraform 0.12 to 0.13 and the aws provider from version 2 to 3. Now I struggle with accessing attributes on empty lists. Previously that was working, now I get errors.

If var.env now is not "production", I get this error:

15:     for dvo in aws_acm_certificate.cert.0.domain_validation_options : dvo.domain_name => {
    |----------------
    | aws_acm_certificate.cert is empty tuple

The given key does not identify an element in this collection value.

Previously, I used count for the aws_route53_record, too, but since I’m supposed to use for_each, which can’t be used with count.

Here the resources

resource "aws_acm_certificate" "cert" {
  domain_name = "*.example.com"
  subject_alternative_names = ["example.com"]
  validation_method = "DNS"

  lifecycle {
    create_before_destroy = true
  }

  count = var.env == "production" ? 1 : 0
}

resource "aws_route53_record" "aws_3" {
  for_each = {
    for dvo in aws_acm_certificate.cert.0.domain_validation_options : dvo.domain_name => {
      name = dvo.resource_record_name
      record = dvo.resource_record_value
      type = dvo.resource_record_type
    }
  }
  zone_id = data.aws_route53_zone.example_com.zone_id
  ttl = 300
  name = each.value.name
  records = [each.value.record]
  type = each.value.type
}

# resource "aws_route53_record" "aws_2" {
#  name = aws_acm_certificate.cert.0.domain_validation_options[0].resource_record_name
#  type = aws_acm_certificate.cert.0.domain_validation_options[0].resource_record_type
#  zone_id = data.aws_route53_zone.example_com.zone_id
#  records = [aws_acm_certificate.cert.0.domain_validation_options[0].resource_record_value]
#  ttl = 300
#
#  count = var.env == "production" ? 1 : 0
# }

How can I fix this so it’s working even if var.env is not "production"?

Thank you