I am writing this from an HP Stream 11
Using a minimal Debian LXQt.
What I haven’t tried so far is to install the System onto an SD card, Boot from that SD Card and install the /Home on the free SDD.
There are pre-made distros which will install and run e.g. GalliumOS -...
If you look at the Page Preview it says 8.50 in (Letter) along the top and 11in down the side.
That isn't A4 it's US Letter.
Try clicking on Properties below Printer to make sure that your printer knows it has and is dealing with A4 paper.
Your first picture shows that the USB stick is formatted to exfat. Did you do this, or did Ventoy do it?
exfat needs some extra bits to make it readable.