Hello Stasy13
I would strongly advise a canvas. Direct to the wall I have tried, the picture is disastrous ! It is a shame
if you have such an expensive unit, without a decent picture !
If you want to save money, you can buy a smaller UST-CLR screen (the LSP7 supports sizes from 90" to 120").
from 90 inches to 120 inches ) .

In principle, I would never use a beamer without a screen. Especially not with a short-distance projector. For such a projector, I would recommend a CLR screen: https://www.digitec.ch/search