Yes. INPUT control directly adjusts input level of the internal microphones and the mic/line input.
What I posted above is how most TS concert tapers would use use the recorder - manually turning limiting OFF, low cut OFF, and setting the recorded file format to whatever you want.
The various SCENES selections set a preset input level which can be further adjusted as required using the INPUT rocker control. But in addition to input level there are other pre-selected settings for each SCENE which you should be aware of if you plan to use the SCENES selector. The settings of each SCENE are detailed on page 12 of the manual.
Based on a look at the rather sparse user manual it looks like gain adjustment using the INPUT rocker provides adjustment over the entire available gain range regardless of the starting level of any SCENES preset. That is unusual for small handheld recorders as there is typically a physical switch or menu switch to select mic-level or line-level input sensitivity. There is also typically a way to turn plug in power to the mic input jack on/off, but I see no such mention of that in the manaul.
You can use SCENES if you like.. as long as one or more of them happen to use the specific combination of settings you want. I'd leave it off.