May be 17 rounds - break and then another 17 rounds. I did not say it's the best and I know it's not soccer, but you will not get the fairness without a system like that.
May be divide the comp in two, then 18 teams play only 18 games away and home, and then have a playoff system with the top 4 of each. I feel like it can work with a bit of creativity.
You need more than 18 teams for this scenario.
Home and away:
Maybe 24 might work better with 2 x 12 team conferences (A and B)
11 Home and 11 away games each = 22 rounds in total (each conference)
Finals:
4 teams from each conference play finals.
1A plays 4B - 1B plays 4A
2A plays 3B - 2B plays 3A
Highest 2 placed winning sides move to finals week 3 (prelim) with highest 2 placed loosing teams getting a chance and move to week 2 to play the lowest 2 winning teams
Lowest 2 placed winners get eliminated
etc, etc, etc
next season conferences determined by finishing order of previous years to mix the conferences up a little.
Advantages:
More games per season
Play each team within conference home and away - A fairer draw within each conference (but also see disadvantages)
Disadvantages:
You WILL miss some derby and traditional rivalry matches.
Brisbane will still get every Friday night home game