Update issues to Fedora 31

After updating from 30 to 31 which took a very very long time(about two hours) , now my computer has two problems:

  1. boot time is now very long (1 min 30 seconds), which used to be 50 seconds.
  2. although gnome-shell is installed and running, when I type gnome-tweaks in terminal, I get this error:

WARNING : Shell not installed or running
WARNING : Error detecting shell
Traceback (most recent call last):
File “/usr/lib/python3.7/site-packages/gtweak/tweaks/tweak_group_shell_extensions.py”, line 218, in init
raise Exception(“Shell not running or DBus service not available”)
Exception: Shell not running or DBus service not available
WARNING : Shell not running
NoneType: None

Additional information:

gnome-shell --version

GNOME Shell 3.34.1


Window manager warning: Display “:0” already has a window manager; try using the --replace option to replace the current window manager.
(gnome-shell:6901): mutter-ERROR **: 10:01:54.840: Failed to start Xwayland: Failed to acquire window manager ownership
== Stack trace for context 0x5646428fe570 ==
Trace/breakpoint trap (core dumped)