I just tested again and it seems to work for me.

Before deleting overcloud-0
 
(undercloud) [CentOS-8 - stack@undercloud ~]$ openstack port list | grep virtual_ip
| 1e282d87-48ec-4a1c-aed7-db2e2738a2db | internal_api_cloud_0_virtual_ip | fa:16:3e:e0:a8:ae | ip_address='172.16.13.45', subnet_id='8ec940ad-d1bb-476c-b305-757dcbc8b874'   | DOWN   |
| 25016e27-8bae-4955-a4af-776a94587a51 | ovn_dbs_virtual_ip              | fa:16:3e:0e:8a:e3 | ip_address='172.16.13.189', subnet_id='8ec940ad-d1bb-476c-b305-757dcbc8b874'  | DOWN   |
| 2eed420c-f92f-4a0e-b00e-bfa8aba27ae2 | redis_virtual_ip                | fa:16:3e:97:d2:7b | ip_address='172.16.13.219', subnet_id='8ec940ad-d1bb-476c-b305-757dcbc8b874'  | DOWN   |
| 49af0ef7-6840-4cd1-9d66-fa2552794eef | external_cloud_0_virtual_ip     | fa:16:3e:9e:d7:60 | ip_address='192.168.100.21', subnet_id='bb69e475-e85c-4277-906b-8e296c9d33ea' | DOWN   |
| b491f13e-f9bd-4b0a-b1a7-f680b5547c00 | control_virtual_ip              | fa:16:3e:62:52:6b | ip_address='192.168.24.11', subnet_id='abc83e41-3ab3-46a6-8bf6-16029bf4af0d'  | DOWN   |
| c2c50e17-1745-46ed-9e95-a1efb54da806 | storage_cloud_0_virtual_ip      | fa:16:3e:d3:60:8c | ip_address='172.16.11.212', subnet_id='fc7912b5-7ab7-4137-bde5-59ed54660a37'  | DOWN   |
| fccabd72-ca36-42b5-862e-ff121ff8b36f | storage_mgmt_cloud_0_virtual_ip | fa:16:3e:1b:c0:cc | ip_address='172.16.12.9', subnet_id='6364c82e-e5f1-4699-9655-4643b6c37514'    | DOWN   |

(undercloud) [CentOS-8 - stack@undercloud ~]$ openstack overcloud delete overcloud-0
Are you sure you want to delete this overcloud [y/N]? y

PLAY [delete ipa entries for overcloud nodes] **********************************
2021-05-14 12:25:58.872234 | 24420171-6e44-b5f4-35ef-000000000009 |       TASK | Check if undercloud is an ipa client
2021-05-14 12:25:59.336429 | 24420171-6e44-b5f4-35ef-000000000009 |         OK | Check if undercloud is an ipa client | localhost
2021-05-14 12:25:59.338512 | 24420171-6e44-b5f4-35ef-000000000009 |     TIMING | Check if undercloud is an ipa client | localhost | 0:00:00.527671 | 0.47s

PLAY [Overcloud Delete] ********************************************************
2021-05-14 12:25:59.367229 | 24420171-6e44-b5f4-35ef-000000000015 |       TASK | Check for required inputs
2021-05-14 12:25:59.408961 | 24420171-6e44-b5f4-35ef-000000000015 |    SKIPPED | Check for required inputs | localhost | item=stack_name
2021-05-14 12:25:59.411479 | 24420171-6e44-b5f4-35ef-000000000015 |     TIMING | Check for required inputs | localhost | 0:00:00.600620 | 0.04s
2021-05-14 12:25:59.419022 | 24420171-6e44-b5f4-35ef-000000000019 |       TASK | Delete service vips used
2021-05-14 12:26:03.837230 | 24420171-6e44-b5f4-35ef-000000000019 |    CHANGED | Delete service vips used | localhost
2021-05-14 12:26:03.838918 | 24420171-6e44-b5f4-35ef-000000000019 |     TIMING | Delete service vips used | localhost | 0:00:05.028079 | 4.42s
2021-05-14 12:26:03.845620 | 24420171-6e44-b5f4-35ef-00000000001a |       TASK | Delete heat stack
2021-05-14 12:29:47.419273 | 24420171-6e44-b5f4-35ef-00000000001a |    CHANGED | Delete heat stack | localhost
2021-05-14 12:29:47.421707 | 24420171-6e44-b5f4-35ef-00000000001a |     TIMING | Delete heat stack | localhost | 0:03:48.610851 | 223.57s
2021-05-14 12:29:47.429990 | 24420171-6e44-b5f4-35ef-000000000017 |       TASK | Workflow notice
2021-05-14 12:29:47.482904 | 24420171-6e44-b5f4-35ef-000000000017 |         OK | Workflow notice | localhost | result={
    "changed": false,
    "msg": "Ansible workflow completed."
}
2021-05-14 12:29:47.484373 | 24420171-6e44-b5f4-35ef-000000000017 |     TIMING | Workflow notice | localhost | 0:03:48.673527 | 0.05s

PLAY RECAP *********************************************************************
localhost                  : ok=4    changed=2    unreachable=0    failed=0    skipped=1    rescued=0    ignored=0   
2021-05-14 12:29:47.489722 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Summary Information ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2021-05-14 12:29:47.490149 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Total Tasks: 5          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2021-05-14 12:29:47.490547 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Elapsed Time: 0:03:48.679721 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2021-05-14 12:29:47.490982 |                                 UUID |       Info |       Host |   Task Name |   Run Time
2021-05-14 12:29:47.491395 | 24420171-6e44-b5f4-35ef-00000000001a |    SUMMARY |  localhost | Delete heat stack | 223.57s
2021-05-14 12:29:47.491835 | 24420171-6e44-b5f4-35ef-000000000019 |    SUMMARY |  localhost | Delete service vips used | 4.42s
2021-05-14 12:29:47.492235 | 24420171-6e44-b5f4-35ef-000000000009 |    SUMMARY |  localhost | Check if undercloud is an ipa client | 0.47s
2021-05-14 12:29:47.492658 | 24420171-6e44-b5f4-35ef-000000000017 |    SUMMARY |  localhost | Workflow notice | 0.05s
2021-05-14 12:29:47.493094 | 24420171-6e44-b5f4-35ef-000000000015 |    SUMMARY |  localhost | Check for required inputs | 0.04s
2021-05-14 12:29:47.493486 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ End Summary Information ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Success.

(undercloud) [CentOS-8 - stack@undercloud ~]$ openstack port list | grep virtual_ip
(undercloud) [CentOS-8 - stack@undercloud ~]$