The repeater question is a whole separate question when it comes to light bulbs.
There are two different zigbee profiles that a lightbulb can use. ZLL (Zigbee light link) is specific to lighting. When connected using ZLL, those bulbs will only repeat for other ZLL devices, creating a mini network typically of just other lightbulbs.
ZHA (zigbee home automation) is a broader category used for most of the zigbee devices that attach to the SmartThings hub directly. In the US, the Osram Lightify bulbs do act as ZHA repeaters. But i haven’t yet seen published confirmation for the EU models.
So the answer is probably, but not certain.
The following is a current topic where community members are working on a device type for one of the newest models in the UK. That would probably be a good place to ask about repeating since the members have those bulbs.