I have also tried a clean install of 8.1, updated to 2022.6.4 - then the official wallbox integration installed.
Do these log errors help?
Error doing job: Task exception was never retrieved
2:09:23 PM – (ERROR) components/wallbox/sensor.py - message first occurred at 2:08:52 PM and shows up 2 times
Error while setting up wallbox platform for number
2:08:22 PM – (ERROR) Number
Error adding entities for domain sensor with platform wallbox
2:08:21 PM – (ERROR) Sensor - message first occurred at 2:08:21 PM and shows up 2 times
2022-06-08 14:09:23 ERROR (MainThread) [homeassistant] Error doing job: Task exception was never retrieved
Traceback (most recent call last):
File "/usr/src/homeassistant/homeassistant/helpers/update_coordinator.py", line 137, in _handle_refresh_interval
await self._async_refresh(log_failures=True, scheduled=True)
File "/usr/src/homeassistant/homeassistant/helpers/update_coordinator.py", line 270, in _async_refresh
update_callback()
File "/usr/src/homeassistant/homeassistant/helpers/update_coordinator.py", line 330, in _handle_coordinator_update
self.async_write_ha_state()
File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 533, in async_write_ha_state
self._async_write_ha_state()
File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 571, in _async_write_ha_state
state = self._stringify_state(available)
File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 539, in _stringify_state
if (state := self.state) is None:
File "/usr/src/homeassistant/homeassistant/components/sensor/__init__.py", line 388, in state
value = self.native_value
File "/usr/src/homeassistant/homeassistant/components/wallbox/sensor.py", line 174, in native_value
round(self.coordinator.data[self.entity_description.key], sensor_round),
TypeError: type NoneType doesn't define __round__ method