Do Dell bios update all in one Package
1- I Create folders in defaultpackagesshare Bios then Dell, then create folder with shortname model and put the last bios uptate. I check all existence in step one
2- I use registry key value condition by checking HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\BIOS\SystemProductName
3- Each condition go to adequate installer
4- installer use /s for silent /r for reboot /p if you set a password system and /l for logging
Adapt this package with yout own model
I don't use this one but it can help you
https://www.lansweeper.com/report/bios-version-audit/