How to fill the values to a shell script from tsv file and create new file from 1st column value

I have a data.tsv file with 100 entries, as below

and I have a template.in script below, that need to fill above values from tsv file

for_example = $ColumnA
testmyhpothesis = $ColumnB $ColumnC
cleandir = $ColumnD $ColumnE
testOutdir = /path/todir/$ColumnD

And create new script file with columnA value

eg:
File 1. Cell 31.in

for_example = Cell 31
testmyhpothesis = Cell 4 Cell 3
cleandir = Cell 5 Cell 8
testOutdir = /path/todir/Cell 5

File 2. Cell 21.in

for_example = Cell 21
testmyhpothesis = Cell 2 Cell 5
cleandir = Cell 6 Cell 9
testOutdir = /path/todir/Cell 6

awk -F '\t' '{for (i = 2; i <= NF; i++) {print $i >> new_file} data.tsv

Here's a solution that makes use of envsubst for replacing the $ColumnXXX in template.in:

#!/bin/bash
{
    # get the names of the variables from the TSV header
    IFS=$'\t' read -r -a varnames
    export "${varnames[@]}" || exit 1

    # read each field into its corresponding variable
    while IFS=$'\t' read -r "${varnames[@]}"
    do
        # replace the expansions in "template.in"
        envsubst "${varnames[*]/#/$}" < template.in > "${!varnames[0]}.in"
    done
} < data.tsv

Using any awk:

$ cat tst.awk
BEGIN { FS="\t" }
NR == FNR {
    tmplt[++numLines] = $0
    next
}
FNR == 1 {
    for ( fldNr=1; fldNr<=NF; fldNr++ ) {
        tag = "$" $fldNr
        tags2fldNrs[tag] = fldNr
    }
    next
}
{
    out = $(tags2fldNrs["$ColumnA"]) ".in"
    for ( lineNr=1; lineNr<=numLines; lineNr++ ) {
        line = tmplt[lineNr]
        for ( tag in tags2fldNrs ) {
            if ( s = index(line,tag) ) {
                fldNr = tags2fldNrs[tag]
                val = $fldNr
                line = substr(line,1,s-1) val substr(line,s+length(tag))
            }
        }
        print line > out
    }
    close(out)
}

<p>

$ awk -f tst.awk template.in data.tsv

<p>

$ head Cell*
==> Cell 21.in <==
#!/bin/bash

for_example = Cell 21
testmyhpothesis = Cell 2 Cell 5
cleandir = Cell 6 Cell 9
testOutdir = /path/todir/Cell 6

==> Cell 31.in <==
#!/bin/bash

for_example = Cell 31
testmyhpothesis = Cell 4 Cell 3
cleandir = Cell 5 Cell 8
testOutdir = /path/todir/Cell 5

That would fail if you could have column tags (names) that are substrings of others, e.g. ColumnA and ColumnAB, and it assumes the values under ColumnA are always unique. That's consistent with the example you provided so post a new question if your example is wrong and you can't figure out how to adapt this to suit your real data.