I'm glad you enjoy the game and thank you for the great feedback.
When you hover over a character you will see 3 coloured rings. These are range indicators. The white is for their attack, the blue for their ability and the yellow for their ulti. You can see range indicators for enemies as well. By placing squishy characters outside of enemy range or by positioning your team so they can all attack one specifically dangerous enemy you can turn the tide of battle.
You can also use positioning to divide enemy groups.
We have on the roadmap to include a tutorial part that explains the range indicators. We're probably gonna bump that up in prio based on your feedback, so thank you for taking the time! :)