Looks like you are actually talking one thing (buying a tent) but wishing for another (making a tent).
I bought a really cheap tent where two reviews said the manufacture process was terrible but the material was spot on. My wife restitched and resealed the whole thing adding strength to every tag and adding a few more, it took her a day to do so. I learned quite a bit about seam sealing from her.
To this day I still believe I should have asked her nicely to make me a tent before she saw one up close and dangerous so to speak. She has since adapted a Vaude poncho to suit me, well it did 45lbs ago. And she has made an ultra light quilted sleep mat for me with rip stop (1.1oz) three layers if kevlar space blanket and two layers of insulating fleece. BUT she refuses to think about making me a tent due to her experience fixing the other one.
As for dyneema have you actually tried using it. People on this forum complain about the sound of drones 40 miles away. Can you imagine the horror stories about the crinkling noises all night in the wind that is normal in the UK wilds, either from the exterior or interior of the tent