Installation:
# CLI installation method after setup file has been downloaded
sudo apt install default-jre -y
username=$(whoami) # Assuming current user is one who has downloaded the file - please change this value to reflect any variances
sudo dpkg -i /home/$username/Downloads/ConnectWiseControl.ClientSetup.deb
sudo apt-get -f install

# Uninstallation:
connectwiseUniqueInstance=$(dpkg -l | grep -oh '\connectwisecontrol-\w*')
sudo dpkg -r $connectwiseUniqueInstance

# Fixing Java error: 'java.lang.UnsatisfiedLinkError: no splashscreen in java.library.path'
#sudo apt remove openjdk-14-jdk-headless -y && sudo apt install openjdk-14-jdk -y
# This works on Lubuntu 20.04
sudo apt remove openjdk-8-jre-headless -y && sudo apt install openjdk-8-jre -y
Troubleshooting:

Unable to Initiate Java Web Console (icedtea-netx):

root@kimlinux:/home/kim# javaws /home/kim/Downloads/ConnectWiseControl.Client.jnlp 
selected jre: /usr/lib/jvm/java-8-openjdk-amd64/jre/
Unable to use Firefox's proxy settings. Using "DIRECT" as proxy type.
java.lang.UnsatisfiedLinkError: no splashscreen in java.library.path
        at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1860)
        at java.lang.Runtime.loadLibrary0(Runtime.java:871)
        at java.lang.System.loadLibrary(System.java:1124)
        at java.awt.SplashScreen$1.run(SplashScreen.java:124)
        at java.awt.SplashScreen$1.run(SplashScreen.java:122)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.awt.SplashScreen.getSplashScreen(SplashScreen.java:121)
        at net.sourceforge.jnlp.Launcher.launchApplication(Launcher.java:517)
        at net.sourceforge.jnlp.Launcher$TgThread.run(Launcher.java:945)

Exception in thread "ConnectWise Control Client" java.lang.RuntimeException: java.lang.UnsatisfiedLinkError: no splashscreen in java.library.path
        at net.sourceforge.jnlp.Launcher$TgThread.run(Launcher.java:968)
Caused by: java.lang.UnsatisfiedLinkError: no splashscreen in java.library.path
        at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1860)
        at java.lang.Runtime.loadLibrary0(Runtime.java:871)
        at java.lang.System.loadLibrary(System.java:1124)
        at java.awt.SplashScreen$1.run(SplashScreen.java:124)
        at java.awt.SplashScreen$1.run(SplashScreen.java:122)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.awt.SplashScreen.getSplashScreen(SplashScreen.java:121)
        at net.sourceforge.jnlp.Launcher.launchApplication(Launcher.java:517)
        at net.sourceforge.jnlp.Launcher$TgThread.run(Launcher.java:945)

Find the installed Java versions: make sure that jre or jdk versions are installed – the headless versions are included upon OS instantiation by default; however, the standard (without headless) is required for Java runtime client to operate properly. This is applicable to both server and client versions of ScreenConnect.

root@kimlinux:/home/kim# which java
/usr/bin/java
root@kimlinux:/home/kim# apt list --installed | grep jdk

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

openjdk-11-jre-headless/focal-updates,focal-security,now 11.0.9.1+1-0ubuntu1~20.04 amd64 [installed,automatic]
openjdk-11-jre/focal-updates,focal-security,now 11.0.9.1+1-0ubuntu1~20.04 amd64 [installed,automatic]
openjdk-14-jdk-headless/focal-updates,now 14.0.2+12-1~20.04 amd64 [installed,automatic]
openjdk-14-jdk/focal-updates,now 14.0.2+12-1~20.04 amd64 [installed]
openjdk-14-jre-headless/focal-updates,now 14.0.2+12-1~20.04 amd64 [installed,automatic]
openjdk-14-jre/focal-updates,now 14.0.2+12-1~20.04 amd64 [installed,automatic]
openjdk-8-jre-headless/focal-updates,focal-security,now 8u275-b01-0ubuntu1~20.04 amd64 [installed,automatic]
openjdk-8-jre/focal-updates,focal-security,now 8u275-b01-0ubuntu1~20.04 amd64 [installed]
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