Should I apt autoremove if it will remove dkms?

I had installed the nvidia-drivers-390, but then I decided I don't need them, so I uninstalled them again. Now I was installing some other package, and apt displayed a ton of unneeded packages that could be apt autoremoved:

  dctrl-tools dkms
  libatomic1:i386 libbsd0:i386 libdrm-amdgpu1:i386
  libdrm-intel1:i386 libdrm-nouveau2:i386 libdrm-radeon1:i386 libdrm2:i386
  libedit2:i386 libelf1:i386 libexpat1:i386 libffi7:i386 libgl1:i386
  libgl1-mesa-dri:i386 libglapi-mesa:i386 libglvnd0:i386 libglx-mesa0:i386
  libglx0:i386 libllvm12:i386 libnvidia-compute-390:i386
  libnvidia-decode-390:i386 libnvidia-encode-390:i386 libnvidia-fbc1-390:i386
  libpciaccess0:i386 libsensors5:i386 libstdc++6:i386 libvulkan1:i386
  libwayland-client0:i386 libx11-6:i386 libx11-xcb1:i386 libxau6:i386
  libxcb-dri2-0:i386 libxcb-dri3-0:i386 libxcb-glx0:i386 libxcb-present0:i386
  libxcb-randr0:i386 libxcb-shm0:i386 libxcb-sync1:i386 libxcb-xfixes0:i386
  libxcb1:i386 libxdmcp6:i386 libxext6:i386 libxfixes3:i386 libxshmfence1:i386
  libxxf86vm1:i386 mesa-vulkan-drivers:i386
  screen-resolution-extra

Whyever should it want to remove dkms ? And can I safely remove the :i386 packages when I have an AMD64 processor ?

While dkms is in the 'main' pocket of the Ubuntu repos, it's not included in a stock install of Ubuntu. It's likely that you added it as a dependency of some other package later.

You are now removing the last packages that depend upon dkms, so there is no longer any need for it. Were there any packages installed that require dkms, apt would not remove it.

If, in the future, you intall a package that depends upon dkms, apt will install it again. Alternately, if it makes you happier, you can simply tell apt to install it.