That's not how projectors work, you can't just beam from an LED screen onto a surface for two main reasons:

1) an LED screen emits light in all directions (which is why you can see it from the side), it would need to emit light only at the screen. Making this work would require putting a microlens over every single individual pixel.

2) Even if you achieved the first step, the amount of light you have will be the same. Spreading the light from a phone screen over an area of several square meters is going to be extremely dim, even if your surface was magically 100% reflective and your room was very dark.

Most projectors use lasers, and in the process of generating enough light also generate an absolute ton of heat. It's one of the main reasons even portable projectors are the size they are, it's just about impossible to cool them if they're any smaller.

The Samsung beam had dedicated hardware, was quite chunky to fit said hardware, and the projector could only be used in a pitch black room.

They literally did this 7 years ago with the Motorola Z series and the insta share projector mod. You can get the phone and the projector real cheap used. Pair it with some SoundCore minis paired together and you have yourself a portable movie theater.

That is a micro projector that attaches to the phone, less of a mod and more of a specialised piece of hardware.

It was also 50 lumens where a typical home theatre projector is more like 2000 lumens.

There's a reason most people own a tv and almost nobody owns a micro projector, they're not very good.

There are also Xperia Touch(G1109) and numerous other AliExpress projectors with Android device integrated. The idea is potentially valid but IME the lamp tech available are just too dim.

You can technically use any display as a projector. You just need to put a huge lens in front of it that is capable of collecting all the light that is being emitted in all directions and focusing it onto the surface. No, it won't be practical, and it definitely won't be bright. But you can use that method to project slides (remember those?) onto a wall by putting them in front of a torch and using a magnifying glass.

I remember the Galaxy Beam having this