erased my start up drive

The best way to restore your Mac to factory settings is to erase your hard drive and reinstall macOS.

That link goes to "How to erase your Intel-based Mac" ~ with detailed specific steps to try & perform.

• How to 'Show All Drive Devices' in Disk Utility for MacOS

https://osxdaily.com/2019/08/16/show-all-devices-disk-utility-mac/

..Invisible in newer systems, the selection to "Show All devices"

is essential to erase All; to leave nothing behind. ~ Then, that is

no longer the cause of the problem you keep finding. The Disk

Utility, when used to Erase the Disk, goes after the entire content

of that physical drive. Not simply some partitions. They all go..

..In Disk Utility on your Mac, you can change the view to show all devices or only volumes in the sidebar..

• View all devices or only volumes in Disk Utility on Mac - Apple Support

https://support.apple.com/guide/disk-utility/view-devices-volumes-disk-utility-mac-dskud6b39edb/mac

[Mojave uses an APFS partition format scheme; & rules differ, compared to older GUID HFS+ partitions.]

You can add/remove systems, and parts, within Volumes; while not necessarily erasing Disks. Confusion.

• The Difference Between a Drive, Disk, Volume, Partition, and Image - make tech easier

https://www.maketecheasier.com/difference-between-disk-drive-volume-partition-image/

• Add, delete, or erase APFS volumes in Disk Utility on Mac - Apple Support

https://support.apple.com/guide/disk-utility/add-erase-or-delete-apfs-volumes-dskua9e6a110/mac

Be sure you attend to specific details and figure what they mean. If you 'Erase a Disk', that usually means

the entire physical drive. While anything less, means you're only erasing a 'Volume' ~ a portion of a drive.

"Disk -or- Volume" = also appears different in Disk Utility.

{..Contents of this say less, yet assumes you know the level of strength in details of those words used..}

• Erase a volume using Disk Utility on Mac - Apple Support

https://support.apple.com/guide/disk-utility/erase-a-volume-dskutl14079/18.0/mac/10.14

• Disk Utility User Guide -'Table of Contents'- Apple Support

Maybe this could be useful. Or maybe not! I'm happier being a few systems behind

and have more than one Mac; mile posts of those times, as 'in situ' reference, here.

Good luck & happy computing!

🌞🌿⛵️🌤🎣🤖🏕🐝⛄️🌻

Boot into recovery mode or Internet recovery mode and install.

See also:

https://support.apple.com/en-us/HT201065