Azure, that´s what I hope for. MJ1 thanks, I was only a bit concerned, because Linus said something about it in the review, but maybe he just critisized the inability of them to be replaced.
Display update: After talking to alibaba manufacturer (yeah, it seems that it is possible to buy a single item from alibaba), they seem to be able to ship the display in multiple versions: Non-touch (often found on amazon), Touchscreen with speakers on the back (good, but not very desireable as they will be covered by the mainboard assembly and there may be no other speakers in the tablet), then touchscreen with side mounted speakers and metal case (looks promising) and what is the most promising for me - caseless version - just the panel, controller board and wiring.
That would allow me to reduce thickness of the device because if my case is at least 12mm thick, their case is at least 8-10mm thick, then add some mounting plate in between and some shroud around and we are at 30mm thickness, which is less than desireable. Now if they ship only the components, I can make my case just thicker enough to be able to mount them. I hope to make it 20mm thick or less. I honestly have a bit of hope that this will become my daily driver and therefore want to design it in a practically usable way.
EDIT: Display ordered from here: Wholesale 10.5 Inch Ips Hd Audio Output Aluminum Alloy Metal Touch Portable Monitor - Buy Portable Gaming Monitor,Gaming Display,Industrial Embedded Monitor Product on Alibaba.com - I ordered it without metal case, without adapter, without HDMI and one USB C cable, it costs 88 USD + shipping + tax (so 150 eur for me because EU). That means only panel, boards, wiring and speakers will arrive. Seller confirmed that it will work via single type-C cable.
Wifi update: One possibility certainly is to use an extender cable and board for the wireless card. But I am also thinking about permanently attaching USB hub inside the case. That means, the TB4 ports would be accessible only from one side, on the other side there would be a display permanently plugged in and a hub permanently plugged in, providing a variety of connectors and internally, one USB port would be occupied by a USB wifi module. It would provide less signal strength than a module with dedicated antennas, but for me wifi range doesn´t matter too much and the advantage of having USB type-A ports embedded sounds very good, as well as not having to bother with extending the second m.2 (wifi) slot.