That’s a loaded question.... I have 5 Xbee’s acting as my backbone for my mesh. They are solid devices and work well with Xiaomi but they are also on the pricier side for pure repeaters.
In this post here is a list of repeaters that work with Xiaomi
The cheapest option are the IKEA modules.
Long term, I would think about getting those bulbs onto their own mesh (yes, 2nd hub). That will take away the headaches you get with them trying to be repeaters
