T-SQL - Inserting 3.5M rows increases the transaction log size to max

Question

Following is the query I am using to parse 3.5M rows of JSON data and insert it into another table.

DECLARE @id_control bigint
    DECLARE @batchSize bigint
    DECLARE @results nvarchar(256)
    DECLARE @NextFetchValue bigint

    SET @results = 1
    SET @batchSize = 20000
    SET @id_control = 0
    

    WHILE (@results > 0)
    BEGIN
        set @NextFetchValue = null
        set @NextFetchValue = cast(@id_control as bigint)+ cast( @batchSize as bigint)
         
     
            set @InsertTableQuery = 'insert into '+@Schemaname+'.'+@Tablename+' (ColId, '+replace(@SQL,'nvarchar(max)','')+')
            select top '+cast(@batchSize as nvarchar(256))+' a.RN, qse.* from(select qs.Query, QS.QId    as RN from tools.QueryStore qs with(nolock)) a                     
                    cross apply openjson(a.Query) 
                    with
                        (
                            '+@SQL+'
                        )qse 
                    where RN > '+cast(@id_control as nvarchar(256))+' and RN <= '+cast(@NextFetchValue as nvarchar(256))

            exec sp_executesql  @InsertTableQuery


           
           SET @results = @@ROWCOUNT
           
     

       -- next batch
       SET @id_control = @id_control + @batchSize
    END

Here is the query output

insert into dbo.Stgtable (ColId, Col1 , Col2 , Col3 , Col4 , Col5 , Col6 , Col7 , Col8 , Col9 , Col10 , Col11 , Col12 , Col14 , Col15 , Col16 , Col17 , Col21 , Col22 , Col23 , Col24 , Col27 , Col28 , Col29 , Col30 , Col31 , Col32 , Col33 , Col34 , Col35 , Col36 )
            select top 20000 a.RN, qse.* from(select qs.Query, QS.QId    as RN from tools.QueryStore qs with(nolock)) a                     
                    cross apply openjson(a.Query) 
                    with
                        (
                            Col1 nvarchar(max), Col2 nvarchar(max), Col3 nvarchar(max), Col4 nvarchar(max), Col5 nvarchar(max), Col6 nvarchar(max), Col7 nvarchar(max), Col8 nvarchar(max), Col9 nvarchar(max), Col10 nvarchar(max), Col11 nvarchar(max), Col12 nvarchar(max), Col14 nvarchar(max), Col15 nvarchar(max), Col16 nvarchar(max), Col17 nvarchar(max), Col21 nvarchar(max), Col22 nvarchar(max), Col23 nvarchar(max), Col24 nvarchar(max), Col27 nvarchar(max), Col28 nvarchar(max), Col29 nvarchar(max), Col30 nvarchar(max), Col31 nvarchar(max), Col32 nvarchar(max), Col33 nvarchar(max), Col34 nvarchar(max), Col35 nvarchar(max), Col36 nvarchar(max)
                        )qse 
                    where RN > 0 and RN <= 20000

During the execution of the query in batches - my transaction log size increases drastically.

How to insert millions of records quickly without increasing the transaction log?