Silent Install
First you need to extract the msi file from the Exe installer. The Exe Installer was created with the WiX Toolset. So you need the dark.exe application from this Toolset to extract the msi file from the exe installer.
dark.exe camtasia.exe /x "c:\path\to\somewhere"
Now use the TechSmith_Deployment_Tool.exe to create a mst file with your wished settings. Afterwards use this command to deploy your application.
CamtasiaInstaller_x64.msi /qn /L* "%temp%\TechSmith Camtasia 2018 18.0.0.3358.log" /norestart ALLUSERS=2 TRANSFORMS="CamtasiaInstaller_x64.mst" TSC_SOFTWARE_KEY="11111-22222-33333-44444-55555"
Silent Uninstall
MsiExec.exe /x {9F0F1C1C-DBBC-4C49-82B3-673B95505BF5} /qn /norestart