Does unity clear Ram if i choose unload assets ?

Hello, Thank you for looking in to my question. I am making a huge open world game and making zone based maps. Where I only load zones once player is near it and destroy the ones he left thus making the game look like open world. I found an asset called SECTR STREAM which unloads objects when not in use. Does this work and can it really give me Ram space. I am just worried that I might cross the RAM limit on IOS which is around 200 to 300 MB for games. All the lighting and shading in the game are from UBER shader and some more. I am using 2048 textures at some places and a bit low at different places and I will optimise the areas to not take more memory by making the level low res when battle is going on.