Access variables,method from a Mono Behaviour without static use.

Hello i am currently trying to work on a univercity project which requires us to make a 3D game and i've been trying to write my own code so i can train more my coding and better understanding of how c# works. Currently i have found some solutions to my problems but they seem quite "heavy" on my Desktop.

So i would like to have some pointers on how to implement or fix my code further to do the following.

My problem is that all my code works if i make the variables i want as static but that would pose problems on the code i would write afterwards. For example.

We have this classes:

 Char_Select : MonoBehaviour // this class requires mono behaviour because it has public gameobjects that need to be set in the inspector.
 
 Base_Character //which doesn't require to inherit Monobehaviour since it only initialization of variables and some functions.
 
 WizardSkills : MonoBehaviour // same as Char_Select

so far i was able to access methods and variables between those classes if i made static the variables and methods that needed to be accessed.Although this seems quite "wrong" and power consuming so i tried to do the following example.

 Char_Select instance = new Char_Select();

then i tried accesing the variables in the Base_Character class but as it seems because Char_Select inherits from mono behaviour i would have to use the GetComponent but as far as i know if i do that the whole class will get added to my character for example a Wizard.

 public class Char_Select : MonoBehaviour
 {
     public GameObject char1_glow;
     public GameObject char2_glow;
     public GameObject char3_glow;
     public Transform ranger;
     public Transform wizard;
     public Transform warrior;
     public bool isClicked = false;
     public int ID = 0;

Lets say this is our variables for Char_Select class

 public class Base_Character 
 {
     public  int Strength; 
     public int Agility; 
     public int Vitality;
     public int Intelligence; 
     public int Wisdom;
     private int level = 1;
     public bool up = false;
     private int xp;
     private int xp_to_level;
     public  bool incombat = false;

And this is the Base_Character class

How would i access without static and without needing to add the Base_Character and the Char_Select class to the gameobject (for example the Wizard) from the following class?

 public class WizardSkills : MonoBehaviour {
 
     public GameObject force;
     private bool shield = false;
     private int reduction; 
     private GameObject target;
 
 }