Ace Tennis Preview is a service operated by an Australian called Steve and all of his tips are free!!
There is a full results history dating back to 2018 with an overall ROI of 2.3% (at the time of adding the profile).
Steve also provides free tennis betting tips for the Betfair Hub. This is the Australian version of the Betting Betfair blog. Each of those selections are supported with insight and they have an ROI of 6.9%.
His Betfair Hub selections are definitely worth considering, perhaps hand pick your favourite selections from his posts, like I do with the Best Bets feature.
It’s an approach I have used with free tennis betting tipsters in the past, rather than backing every single one of their free tips.