May I ask what video card you have?
My GPU is an NVIDIA GeForce GTX 1060, and my CPU is a Ryzen 7 2700X. I would've expected the game to run better, considering it runs on both the base PS4 and Nintendo Switch at 30FPS, and there's better looking games that run higher than 60FPS at 1080p for me.
That said, there is an upcoming update that is going to add graphics options, "optimizations", and mouse support, according to Koei Tecmo's recent announcements.
If they did these things, fixed the physics issues above 30FPS, and got rid of the eight way movement (and used analog movement instead), I would actually recommend picking it up on Steam. The game itself is really good.
EDIT: Now that actual graphics options, and keyboard/mouse support (setting aside the option for separate controls in battle, and no mouse cursor support in menus) has been added with a patch, I would actually recommend this game now.