Do you really think 2 - 3 centivolts is that much of a big deal?
If you do really care about cell cycle life you should reduce the maximum charging voltage quite a bit more, as much as well below 4V (14/15 Vmax or 3.92V for 4.2Vmax cells) for maximum cycle life.
There are slot Vout resistor divider mods available for the Lii-100:
How to fix high charge voltage in Liitokala Lii-100 and how to make lower charge currents
Also, DC/DC CC/CV modules are super cheap and readily available at eBay/AliExpress and other sources.
Cheers ^:)