How many times are we going to go over this? When this game was designed DX12 was not a thing and wasn't just until recently Windows 10 became the majority OS.
Most of the hybrid games where you get both 11 and 12 the 12 version runs worse than the 11 one. The game has to be designed for that platform from the beginning to see true results. Now we are talking a whole new game instead.
If they refused to go with DX12 for obvious reason (I do say that I get it why they did it), then they should keep that in mind and design the game to be playable on DX11. That means not being so ambitious regarding things such as AI (which in the end is not that good and worth the impact on the performance), maybe handle PbB a bit differently too and other aspects... I can imagine Planet Coaster being "worse" in many ways, yet, it would be great game and maybe even playable.
This way, I know Frontier´s game are noth worth buying day 1 and I will consider buying them when they are 5 EURO years after the release... Why should I spent so much money on something I cannot play properly, right?
My last hope at this point is promised QoL update... Years after the release...