If you have a MacBook with an Apple silicone chip (M1 or M2 processor) then you can get a blurred background on your videos inside of Tella.
Set up your video by pressing New Video.
Then go up to your Mac menu bar, click on the little control switch icon, and then click on Video Effects.
It gives you a blurred background which you can control by toggling the Portrait Button on and off.
This will work for you across multiple apps. So if you need to use this on a video calling software then you can also just switch it on from there.
While you have it on, anytime you open up Tella, you will always have a blurred background by default.