To clarify, and add to confusion at the same time:
Lane Keep Assist and Lane Follow Assist have changed in behaviour, meaning and symbols over the years.
I know for certain that only the camera is used by LKA/LFA on previous generation autonomous driving vehicles that are not equipped with smart cruise control and automatic lane changing.
The meaning of Follow in the literature seems to have changed: on more recent vehicles which are equipped with more advanced autonomous driving aids, LFA describes following the lane of traffic even through lane changes.
I believe that the OP's car, due to the model year (2019) and the symbols (car between solid lines, separate steering wheel) is the MY2020 behaviour change.
The radar is not involved in Lane Keep Assist and Lane Follow Assist on such models, whether with or without smart cruise control and/or radar.
E.g. My Stonic does not have cruise control but has a radar, used for other functions such as emergency impact avoidance etc.
On the OPs model, LKA (Lane Keep Assist) refers to the ability to use lane markings to keep the vehicle within the detected road markings, only nudging the steering wheel if the drivers veers off to the side. When disabled via the button on the steering wheel, this nudging is disabled, but the Lane Departure Warning system is still active.
The Lane Follow Assist (active when the steering wheel symbol shows, like in the OP's picture) is a more advanced alternative to LKA and behaves differently: it uses either the lane markings (if detected), the vehicle in front (if detected), or both.
It does it all through the same camera used by the LKA (which is why LKA and LFA symbols are both visible when LFA is activated).
LFA, unlike LKA, will keep the vehicle centred in the lane, using the combined presence of lane markings and/or a vehicle in front.
Which means LFA works even in situations where the LKA would not function.
It is common, when LFA is enabled, to see the steering wheel symbol on the dash illuminated green, but the lane+vehicle symbol in white: this indicated a vehicle in front has been detected and the steering is being actively controlled, but no lane markings were detected.