Hi
You can try Howard leather conditioner (from selfix DIY store) or Zymol leather conditioner (from home fix DIY store).
The zymol brand is lighter meaning it is less oily and absorbs quite well. The Howard brand has beeswax so it is oilier and takes a longer time for the leather to absorb. For new sofa, I find zymol is good enough, u can try their leather cleaner as well if yr sofa becomes dirty otherwise leather conditioner is gd enough.
I tried Howard cos my sofa starts to crack n I find it more moisturizing, but I do not like that it is too oily as it takes a longer time for the leather to absorb it. Hope this helps.