I’m sorry, after looking into it you can’t adjust the inverter to lithium with just the controls available.
The easysolar is 2 devices in one, both need to be set to lithium.
The inverter itself can be programmed with VE configure but i don’t know if it has a lithium preset and i don’t know what cable you need to program it. The manual doesn’t mention the MK3-USB cable but it probably works. If there is no lithium preset you can set the voltages manually.
Alternatively you can check if the dipswitch setting for OPzV batteries on the inverter has a usable voltage for your lithium battery.
The integrated MPPT solar charger can be set to lithium with the rotary switch mentioned in the manual. Indeed the inverter needs to be opened to access this.
The manual is for both the 12V and 24V versions.