Your system information

• Steam client version (build number or date): 2020-08-30
• Distribution (e.g. Ubuntu): Ubuntu 18.04.5 LTS
• Opted into Steam client beta?: Yes
• Have you checked for system updates?: Yes

Please describe your issue in as much detail as possible:

Yesterday I updated my system (NVidia driver included, I am now in version 450.66)
Today my steam does not work:

$ steam
Running Steam on ubuntu 18.04 64-bit
STEAM_RUNTIME is enabled automatically
Pins up-to-date!
Steam client's requirements are satisfied
/home/seb/.steam/ubuntu12_32/steam
[2020-08-30 10:04:57] Startup - updater built Aug 29 2020 00:52:02
[2020-08-30 10:04:57] Opted in to client beta 'publicbeta' via beta file
You are in the 'publicbeta' client beta.
Installing breakpad exception handler for appid(steam)/version(1598665466)
libGL error: No matching fbConfigs or visuals found
libGL error: failed to load driver: swrast
SteamUpdateUI: An X Error occurred
X Error of failed request:  GLXBadContext
SteamUpdateUI: An X Error occurred
X Error of failed request:  BadValue (integer parameter out of range for operation)
Major opcode of failed request:  151 (GLX)
Minor opcode of failed request:  3 (X_GLXCreateContext)
Value in failed request:  0x0
Serial number of failed request:  45
xerror_handler: X failed, continuing
Major opcode of failed request:  151 (GLX)
Minor opcode of failed request:  6 (X_GLXIsDirect)
Serial number of failed request:  46
xerror_handler: X failed, continuing
Looks like steam didn't shutdown cleanly, scheduling immediate update check
[2020-08-30 10:04:57] Loading cached metrics from disk (/home/seb/.steam/package/steam_client_metrics.bin)
Installing breakpad exception handler for appid(steam)/version(1598665466)
[2020-08-30 10:04:57] Checking for update on startup
[2020-08-30 10:04:57] Checking for available updates...
[2020-08-30 10:04:57] Downloading manifest: client-download.steampowered.com/client/steam_client_publicbeta_ubuntu12
Installing breakpad exception handler for appid(steam)/version(1598665466)
[2020-08-30 10:04:58] Download skipped by HTTP 304 Not Modified
[2020-08-30 10:04:58] Nothing to do
[2020-08-30 10:04:58] Verifying installation...
[2020-08-30 10:04:58] Performing checksum verification of executable files
[2020-08-30 10:04:58] Verification complete
Loaded SDL version 2.0.13-5919606
Gtk-Message: 10:04:59.378: Failed to load module "gail"
Gtk-Message: 10:04:59.378: Failed to load module "atk-bridge"
libGL error: No matching fbConfigs or visuals found
libGL error: failed to load driver: swrast
Steam: An X Error occurred
X Error of failed request:  GLXBadContext
Major opcode of failed request:  151
Serial number of failed request:  52
xerror_handler: X failed, continuing
Steam: An X Error occurred
X Error of failed request:  BadValue (integer parameter out of range for operation)
Major opcode of failed request:  151
Value in failed request:  0x0
Serial number of failed request:  51
xerror_handler: X failed, continuing
Steam: An X Error occurred
X Error of failed request:  BadMatch (invalid parameter attributes)
Major opcode of failed request:  151
Serial number of failed request:  53
xerror_handler: X failed, continuing
assert_20200830100457_1.dmp[10990]: Uploading dump (out-of-process)
/tmp/dumps/assert_20200830100457_1.dmp
/home/seb/.steam/steam.sh: line 750: 10967 Segmentation fault      (core dumped) $STEAM_DEBUGGER "$STEAMROOT/$STEAMEXEPATH" "$@"
seb@my-host:~$ assert_20200830100457_1.dmp[10990]: Finished uploading minidump (out-of-process): success = yes
assert_20200830100457_1.dmp[10990]: response: CrashID=bp-116ecc55-3154-4afe-9152-1fec52200830
assert_20200830100457_1.dmp[10990]: file ''/tmp/dumps/assert_20200830100457_1.dmp'', upload yes: ''CrashID=bp-116ecc55-3154-4afe-9152-1fec52200830''

Steps for reproducing this issue:

1. Ubuntu 18.04.5 LTS
2. Last version of nvidia drivers: 450.66
3. System up to date
4. Just launch steam as usual