In order for Dell and Lenovo drivers to show as applicable when deploying them as 3rd Party updates using Dell or Lenovo's 3rd-Party update catalogs in Configuration Manager, you will need to ensure that the "Dell OpenManage Inventory Agent" (for Dells) and the "Lenovo Updates Catalog Agent" (for Lenovos) are included in your driver updates deployments.

In environments I manage, all update groups are managed via ADRs, with subsequence powershell scheduled tasks automating deployments each month to our divided up groups (similar to how some places have rings set up), so I make sure my ADR managing my chipsets updates group grabs them both. If you are managing your deployments manually (why are you doing this, contact me here or on Twitter for help automating this all - it won't take long and will save you hours and hours of time each month!) you'll need to just remember to grab them.

Once these are in place, the system will show the remaining drivers as applicable and download/install them during an install updates step as long as they are deployed to the device (IE: Unknown Systems for fresh images).

Hope this helps!