Conditional Formatting

Named ranges used:
MaxAndMins =Test!$K$3:$L$35
MaxVals =Test!$K$3:$K$35
MinVals =Test!$L$3:$L$35
supplier_1 =Test!$D$3:$D$35
supplier_2 =Test!$E$3:$E$35
supplier_3 =Test!$F$3:$F$35
supplier_4 =Test!$G$3:$G$35
supplier_5 =Test!$H$3:$H$35

Each row of the sample data has a max and a min value. Use two helper columns to extract the max and mins for each row, then use

=SUMPRODUCT(--(INDIRECT(M4)=INDEX(MaxAndMins,,ISEVEN(COLUMN())+1)))

M4:V4 supplier names referring to ranges
ISEVEN(COLUMN())+1) calculates the column of the max/min table/array to use

---

Modify, reduce your conditional format formulas (choose four colors)
highlight min/max for each column:

=D3=MIN(INDEX($D$3:$H$35,,COLUMN(A1)))
=D3=MAX(INDEX($D$3:$H$35,,COLUMN(A1)))

highlight min/max for each ROW:
=D3=MIN(INDEX($D$3:$H$35,ROW(A1),))
=D3=MAX(INDEX($D$3:$H$35,ROW(A1),))