Hi,
I have been looking for this filter for some time now. I have read several stories of people that replaced their back glass with an aftermarket one and lost LiDAR functionality this way. I found some glass 940 nm (I believe this is the wavelength of the LiDAR modules in iPhones) filters. They block everything around that wavelength including visible light. the ones I found (Aliexpress) could probably fit between the back glass and the sensor. But I'm not convinced this is the best solution. They're made of glass and can't be cut easily to the round lidar hole shape. I'm still looking for a plastic or sticker type alternative. Your best bet in the meantime is probably to use replacement housing from a reputable source. If its from an original iPhone, it'll definitely have the right kind of filter installed.