Firefox is so laggy after wake up sleep

When my device is idle, it just lock itself and wait.
When I am logging in and switching tabs between firefox, it is so laggy that it takes upto 4-10 minutes to respond. And also sometimes it crashes and I have to restart my sytsem.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: firefox 85.0+build1-0ubuntu0.20.04.1
ProcVersionSignature: hostname 5.8.0-41.46~20.04.1-generic 5.8.18
Uname: Linux 5.8.0-41-generic x86_64
AddonCompatCheckDisabled: False
ApportVersion: 2.20.11-0ubuntu27.16
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: balashanmugam 1437 F.... pulseaudio
 /dev/snd/pcmC0D0p: balashanmugam 1437 F...m pulseaudio
 /dev/snd/timer: balashanmugam 1437 f.... pulseaudio
BuildID: 20210118153634
CasperMD5CheckResult: skip
Channel: Unavailable
CurrentDesktop: ubuntu:GNOME
Date: Mon Feb 8 21:47:55 2021
ExecutablePath: /usr/lib/firefox/firefox
ForcedLayersAccel: False
InstallationDate: Installed on 2021-02-05 (2 days ago)
InstallationMedia: Ubuntu 20.04.2 LTS "Focal Fossa" - Release amd64 (20210204)
IpRoute:
 default via 192.168.0.1 dev ens33 proto dhcp metric 100
 169.254.0.0/16 dev ens33 scope link metric 1000
 192.168.0.0/24 dev ens33 proto kernel scope link src 192.168.0.118 metric 100
NoProfiles: True
ProcEnviron:
 LANGUAGE=en_IN:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_IN
 SHELL=/bin/bash
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
RunningIncompatibleAddons: False
SourcePackage: firefox
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 08/10/2020
dmi.bios.vendor: VMware, Inc.
dmi.bios.version: VMW71.00V.16722896.B64.2008100651
dmi.board.name: 440BX Desktop Reference Platform
dmi.board.vendor: Intel Corporation
dmi.board.version: None
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 1
dmi.chassis.vendor: No Enclosure
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnVMware,Inc.:bvrVMW71.00V.16722896.B64.2008100651:bd08/10/2020:svnVMware,Inc.:pnVMware7,1:pvrNone:rvnIntelCorporation:rn440BXDesktopReferencePlatform:rvrNone:cvnNoEnclosure:ct1:cvrN/A:
dmi.product.name: VMware7,1
dmi.product.version: None
dmi.sys.vendor: VMware, Inc.