There is no such thing as the Tesla Model Y safe charge zone. The Tesla Model Y is meant to be driven a lot or a little and charged as needed to complete the trip with a reasonable margin of remaining battery charge. Some Model Y owner's will make a familiar trip and know they can arrive at their destination or back home with less than 5% state of charge (SOC) spring, summer and fall while adjusting this margin upwards for winter temperatures.
Before you take your first trip sit down with A Better Route Planner (ABRP) and plan a few trips. ABRP will show you the available charging locations, length of stop, kWh to be added (and estimated cost) and how far to the next stop or your destination. You can adjust ABRP for starting battery SOC, arriving at Supercharger SOC and SOC at the destination. After planning a few trips using ABRP you will know with a high level of confidence whether you will be able to complete the trip with only one charging stop or without stopping to charge, arriving at your destination with a lower remaining battery charge. You can plan on a 90% (departure SOC) /10% (arrival SOC) or 80% (departure SOC) / (down to 20% to 30% SOC) for departure SOC and Supercharger / destination arrival SOC; it is totally your choice.
You can better predict the energy consumption and resulting range for a trip if you know the electric vehicle's usable battery capacity, average highway speed, road conditions, elevation changes, wind, temperature as well as passenger and cargo load. A trip of 160 miles without charging the Tesla Long Range Model Y might leave you with another 100 miles of range or only 25 miles depending on these variables.
If you use the Tesla Navigation system or plan your charging stops using ABRP and stop to charge where and when these tools indicate you should charge you will not have any issues or concerns with running out of charge or running down the battery SOC lower than your comfort level.
There is also a built in battery reserve; the Tesla Model Y has been shown to travel an additional 10 to 12 miles after the battery/range indicator displays 0 miles of range. Of course you would only want to use this reserve in an emergency. For all other scenarios where you are concerned that you don't have sufficient charge you can lower your highway speed. A 5 MPH highway speed reduction will net you almost 10% better efficiency and range. 10 MPH lower speed will double that figure.