WHY LOCATION MATTERS
Your players still have to reach the server.
The Minecraft server can be identical in Dallas and Sydney, but the network path is not. Distance, ISP routing and congestion all affect latency. There is no magic city that is fastest for everyone.
If your group is mostly in North America, start with Dallas. If your group is mostly in Australia or New Zealand, start with Sydney. Mixed group? Pick the location closest to the largest share of players.
Same free resources3 GB RAM, 2 CPU cores and 10 GB storage in either location.
Same server featuresJava, Bedrock, plugins, mods, file access and a RecoilHost address.
No card requiredThe free plan is still free no matter which location you choose.