awk to find match using unique id between two files and append data to second file - awk

Question

In the awk below I am trying to skip the # in f1 and match $4 in f1 with $6 of f2 and if there is a match the contents in $5 in f1 are appended to $8 in f2.
I added comments as well.
f1 tab-delimited
#
#
chr1 2019345 2030758 GABRD {There is a lot of text here}
f2 tab-delimited
chr1 2028270 2028270 G A GABRD This has text in it.
chr1 2028297 2028302 CAT C GABRD This has text in it.
chr1 2229406 2229406 A G SKI This has text in it.
chr1 2304553 2304553 G A SKI This has text in it.
chr1 2306636 2306636 C T SKI This has text in it.
desired tab-delimited
chr1 2028270 2028270 G A GABRD This has text in it. {There is a lot of text here}
chr1 2028297 2028302 CAT C GABRD This has text in it. {There is a lot of text here}
chr1 2229406 2229406 A G SKI This has text in it. unknown
chr1 2304553 2304553 G A SKI This has text in it. unknown
chr1 2306636 2306636 C T SKI This has text in it. unknown
awk
awk '/^[^#]/ # skipping lines starting with # in f1
FNR==NR{ # checking condition which will be TRUE when f2 is being read.
a[$4]=$6 # creating array a with index of $4 and value of $6 here.
next # next will skip all further statements from here.
}
{
print $0,($4 in a?a[$4]:"unknown") # Printing current line and checking if 1st field is there in and print a[$4] else print unknown.
}' f1 f2 # close and inputs

Answer 1

Assumptions:
skip all lines (all files) that start with a #
f1/$5 does not contain any embedded tabs
if f1/$4 == f2/$6 then replace f2/$8 with f1/$5 else set f2/$8 = "unknown"
One awk idea:
awk '
BEGIN { FS=OFS="\t" }
/^#/ { next }
FNR==NR { a[$4]=$5; next }
{ $8= ($6 in a) ? a[$6] : "unknown" }
1
' f1 f2
This generates:
chr1 2028270 2028270 G A GABRD This has text in it. {There is a lot of text here}
chr1 2028297 2028302 CAT C GABRD This has text in it. {There is a lot of text here}
chr1 2229406 2229406 A G SKI This has text in it. unknown
chr1 2304553 2304553 G A SKI This has text in it. unknown
chr1 2306636 2306636 C T SKI This has text in it. unknown