Atera and Splashtop, by default, cannot be started in safe mode. But by tweaking a few registry keys, you can open them in Safe Mode with Networking.

To use Atera and Splashtop in Safe Mode with Networking, add the following registry keys:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot\Network\Splashtop Inc.]
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot\Network\AteraAgent]
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot\Network\SplashtopRemoteService]

Running the following commands can also automate the process:

REG ADD "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot\Network\Splashtop Inc."
REG ADD "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot\Network\SplashtopRemoteService"
REG ADD "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot\Network\AteraAgent"