I would like to use an inline badge with v3, but there is no documentation on badge position for v3.
You can make the badge inline in V3 with just Javascript it's just not documented yet.
Set your render parameter to explicit and add a onload parameter for the callback, onRecaptchaLoadCallback for example.
Then set up your callback like so and don't forget to enter the id/DOM node of where you want your badge to go, in this case, the id is inline-badge.
Example
Source
Note:
Valid values for 'badge' are 'inline', 'bottomleft', 'bottomright', and 'bottom'.
'bottom' and 'bottomright' are synonyms.