If you find your avatar stuck while playing a Roblox game, then you are able to reset its position to the original spawn point. To find out how you can do so in the PlayStation 4 version, you can take a look at this guide from Seeking Tech.
1. While inside a Roblox experience, press the Options button on the DualShock 4 or DualSense to open the Roblox menu.
2. In the pop-up menu, select Respawn Character.
3. You will be asked the following question:
Are you sure you want to reset your character?
Here, you need to select the Reset option.
4. Your character should respawn to its original position when you first loaded into the experience.