There really is no good solution here as you have to compromise on something. I can offer the schedule below, where the compromise is that team 2 competes in 8 matches, while the other teams only have 7 matches each, but the schedule does have teams play each game once or twice, and all opponents once or twice.
G1 G2 G3 G4 G5 G6
R1 (1 4) (2 3) (- -) (- -) (- -) (- -)
R2 (- -) (- -) (3 5) (1 2) (- -) (- -)
R3 (- -) (- -) (- -) (- -) (2 4) (1 5)
R4 (- -) (4 5) (- -) (- -) (1 3) (- -)
R5 (2 5) (- -) (- -) (3 4) (- -) (- -)
R6 (- -) (- -) (1 4) (- -) (- -) (2 3)
R7 (3 5) (1 2) (- -) (- -) (- -) (- -)
R8 (- -) (- -) (2 4) (1 5) (- -) (- -)
R9 (- -) (- -) (- -) (- -) (2 5) (3 4)
I thought about having 7 games, but then the best number of rounds would be 14 which is well over your limit of 10.