To remove all remnants of Sentinel One you use the installer .exe package without having a passphrase or site key

Download the SentinelOne Installation package in exe format of the same version or greater than the sentinelone agent you have installed

Boot the computer into safe mode

Get an administrative cmd.exe prompt and then run the installer with the following parameters

SentinelOneInstaller_windows_64bit_v24_1_4_257.exe -c -k "1" -t 1

Note the -k is normally the passphrase and the -t is the site token but you can just specify 1 as shown