Xorg fails to start on nvidia-435

the whole story is like this. at first i had my nvidia gpu disabled at all by bbswitch. then i decided to turn it on. reversed all actions from https://github.com/Bumblebee-Project/bbswitch and had my GPU back alive. then i decided to use bumblebee to optirun apps. i had no success, so i removed all of these installations and, as i think, fresh installed nvidia-435 from driver manager on Linux Mint 19.3. after reboot login screen is not appearing. from another tty(Ctrl+Alt+F1) i tried running startx but it freezes. i hear login sound but the image is frozen on console. what may be wrong with all of this?
here’s some information

$ uname -a
Linux neo-machine 4.15.0-76-generic #86-Ubuntu SMP Fri Jan 17 17:24:28 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
$ lspci -k | grep -A 2 -E "(VGA|3D)"
00:02.0 VGA compatible controller: Intel Corporation HD Graphics 5500 (rev 09)
	Subsystem: ASUSTeK Computer Inc. HD Graphics 5500
	Kernel driver in use: i915
04:00.0 3D controller: NVIDIA Corporation GM108M [GeForce 940M] (rev a2)
	Subsystem: ASUSTeK Computer Inc. GM108M [GeForce 940M]
	Kernel driver in use: nouveau

i still have this, although i apt purged all nvidia packages:

$ dpkg --list | grep nvidia
ii  libnvidia-compute-435:i386                                  435.21-0ubuntu0.18.04.2                                     i386         NVIDIA libcompute package
ii  libnvidia-decode-435:i386                                   435.21-0ubuntu0.18.04.2                                     i386         NVIDIA Video Decoding runtime libraries
ii  libnvidia-encode-435:i386                                   435.21-0ubuntu0.18.04.2                                     i386         NVENC Video Encoding runtime library
ii  libnvidia-fbc1-435:i386                                     435.21-0ubuntu0.18.04.2                                     i386         NVIDIA OpenGL-based Framebuffer Capture runtime library