I've used the same NFS server to deploy 4.3 without issue, and I ran the nfs-check.py script to verify that the NFS share was correctly provisioned.
[ INFO ] TASK [ovirt.hosted_engine_setup : Copy local VM disk to shared storage]
[ INFO ] changed: [localhost]
[ INFO ] TASK [ovirt.hosted_engine_setup : Remove temporary entry in /etc/hosts for the local VM]
[ INFO ] changed: [localhost]
[ INFO ] TASK [ovirt.hosted_engine_setup : Start ovirt-ha-broker service on the host]
[ INFO ] changed: [localhost]
[ INFO ] TASK [ovirt.hosted_engine_setup : Initialize lockspace volume]
[ INFO ] TASK [ovirt.hosted_engine_setup : Workaround for ovirt-ha-broker start failures]
[ INFO ] changed: [localhost]
[ INFO ] TASK [ovirt.hosted_engine_setup : Initialize lockspace volume]
[ INFO ] changed: [localhost]
[ INFO ] TASK [ovirt.hosted_engine_setup : Start ovirt-ha-agent service on the host]
[ INFO ] changed: [localhost]
[ INFO ] TASK [ovirt.hosted_engine_setup : Exit HE maintenance mode]
[ INFO ] changed: [localhost]
[ INFO ] TASK [ovirt.hosted_engine_setup : Check engine VM health]
[ ERROR ] fatal: [localhost]: FAILED! => {"attempts": 180, "changed": true, "cmd": ["hosted-engine", "--vm-status", "--json"], "delta": "0:00:00.186082", "end": "2020-05-26 20:05:40.063450", "rc": 0, "start": "2020-05-26 20:05:39.877368", "stderr": "", "stderr_lines": [], "stdout": "{\"1\": {\"host-id\": 1, \"host-ts\": 2500, \"score\": 0, \"engine-status\": {\"vm\": \"down_unexpected\", \"health\": \"bad\", \"detail\": \"Down\", \"reason\": \"bad vm status\"}, \"hostname\": \"ovirthost02.po-lite.local\", \"maintenance\": false, \"stopped\": false, \"crc32\": \"3b77b8b8\", \"conf_on_shared_storage\": true, \"local_conf_timestamp\": 2500, \"extra\": \"metadata_parse_version=1\\nmetadata_feature_version=1\\ntimestamp=2500 (Tue May 26 20:05:36 2020)\\nhost-id=1\\nscore=0\\nvm_conf_refresh_time=2500 (Tue May 26 20:05:36 2020)\\nconf_on_shared_storage=True\\nmaintenance=False\\nstate=EngineUnexpectedlyDown\\nstopped=False\\ntimeout=Wed Dec 31 19:47:59 1969\\n\", \"live-data\": true}, \"global_maintenance\": false}", "stdout_lines": ["{\"1\": {\"host-id\": 1, \"host-ts\": 2500, \"score\": 0, \"engine-status\": {\"vm\": \"down_unexpected\", \"health\": \"bad\", \"detail\": \"Down\", \"reason\": \"bad vm status\"}, \"hostname\": \"ovirthost02.po-lite.local\", \"maintenance\": false, \"stopped\": false, \"crc32\": \"3b77b8b8\", \"conf_on_shared_storage\": true, \"local_conf_timestamp\": 2500, \"extra\": \"metadata_parse_version=1\\nmetadata_feature_version=1\\ntimestamp=2500 (Tue May 26 20:05:36 2020)\\nhost-id=1\\nscore=0\\nvm_conf_refresh_time=2500 (Tue May 26 20:05:36 2020)\\nconf_on_shared_storage=True\\nmaintenance=False\\nstate=EngineUnexpectedlyDown\\nstopped=False\\ntimeout=Wed Dec 31 19:47:59 1969\\n\", \"live-data\": true}, \"global_maintenance\": false}"]}
[ INFO ] TASK [ovirt.hosted_engine_setup : Check VM status at virt level]
[ INFO ] TASK [ovirt.hosted_engine_setup : Fail if engine VM is not running]
[ ERROR ] fatal: [localhost]: FAILED! => {"changed": false, "msg": "Engine VM is not running, please check vdsm logs"}