Continuing this discussion.
I'm using DirectX because I'm also using the VR mod, which doesn't work with Vulkan. I also have about a dozen other mods added as well. But, be that as it may, my setup was working fine pre-patch. Barely any noticeable fps drops anywhere. I could take out a spawner without any slowdowns. Now, post-patch, the game turns into a slideshow when attacking spawners, or walking around my base, or sailing, or mining, etc. I even turned off Steam supersampling (didn't help). I also tried adjusting all in-game graphics settings to their lowest (also doesn't help, and most were already disabled anyway for the on/off options).
Again--and not to beat a dead horse here--all was working fine before this latest patch. Now it's a stuttering mess, and seemingly randomly at that, but also as mentioned it gets worse the longer I'm playing. It's essentially unplayable for me right now (in VR anyway, which is the only way I game anymore), so I might just wait and come back to the game with the next patch and try it again then to see if the issue gets resolved. At this point, that's probably my best option.
Fun game though, I love playing it. The environment is amazing.