How to design a database for student records and keep track of current and previous school years

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SQL

SQL-Server

What's the best way to design a students registration records and keep tracks of previous school years?

What I have tried:

I have a table like this:

CREATE TABLE [dbo].[Students] (
    [StudentID]          INT             IDENTITY (1, 1) NOT NULL,
    [StudentNumber]      NVARCHAR (50)   NOT NULL,    
    [EnrolmentDate]      DATE            NULL,
    [Class]              NVARCHAR (50)   NOT NULL,
    [StudentSurname]     NVARCHAR (60)   NOT NULL,
    [StudentFirstNames]  NVARCHAR (60)   NOT NULL, 
    [FatherSurname]      NVARCHAR (100)  NULL,
    [FatherNames]        NVARCHAR (100)  NULL,    
    [MotherSurname]      NVARCHAR (100)  NULL,
    [MotherNames]        NVARCHAR (100)  NULL,
    [SchoolYear]         NVARCHAR (50)   NOT NULL, 
    [StudentPicture]     VARBINARY (MAX) NULL,
    CONSTRAINT [PK_Students] PRIMARY KEY CLUSTERED ([StudentID] ASC),
    CONSTRAINT [IX_Students] UNIQUE NONCLUSTERED ([StudentNumber] ASC),
    CONSTRAINT [FK_Students_AcademicYear] FOREIGN KEY ([SchoolYear]) REFERENCES [dbo].[AcademicYear] ([SchoolYear]) ON UPDATE CASCADE
);

I also have other tables for SchoolFees, MarksEntry, SchoolYear, etc.
So far everything works well for current year, I an just select where SchoolYear = current year, whether it's list of students, ,marks or fees paid/unpaid.

The challenge is to access data from previous years, I haven't figured out how to design the database or add a column to keep track of previous year.
When a student passes the exam, he/she promoted to a different class, so what I update in the Students table is: Class and SchoolYear, the rest of data remain the same like student number and other details.
So if I have a student in class 1B in school year 2020-2021 and promote to class 2B in year 2021-2022, the records of this student in class 1B in 2020-2021 are still in database but no longer accessible because that student no longer exist, their records have been modified.
What's the best and easy solution not to duplicate a student records but somewhat keep track of previous classes and school years when promoting a student to a different class?