Erased main HDD off device and now no hard drive can be found.

From your Internet Recovery>Disk Utility>View>Show All Devices> your parent drive.

You need to erase/format the parent drive.

This would be drive level not container/volume level.

How to reinstall macOS from macOS Recovery: https://support.apple.com/en-us/HT204904

Try an SMC reset and a PRAM reset (hold the PRAM reset for at least three chimes so it activates several times).

Does this laptop contain the original Apple SSD or a third party SSD?

If it contains the original Apple SSD and it does not show up after the resets, then your SSD has died.

If you are using a third party SSD, then you may need to be booting with at least macOS 10.13+. Your screenshot of Disk Utility shows you are using macOS 10.12 or earlier.

You did not answer my very important question. Regardless, either the original Apple SSD has failed or you are using a third party internal SSD. If you are using a third party SSD, then installing a later version of macOS may not work because it requires a system firmware update to be installed which requires an original Apple SSD to be installed internally. You should be able to reinstall the last working version of macOS to the laptop.

Assuming a third party SSD is installed in this laptop, then depending on what has already been done you can try booting into Recovery Mode (Command + R) to reinstall the last OS which was installed on this laptop (in theory anyway). Since Catalina wasn't installed on this laptop, then I don't think you will be able to install Catalina with a third party SSD installed, but you can try by booting into Internet Recovery Mode (Command + Option + R). Make sure to use @leroydouglas' post as a guide on how to erase the SSD if it is seen in Recovery Mode/Internet Recovery Mode.

I would suggest creating a macOS 10.13 High Sierra USB installer using these instructions since it should work even with a third party SSD installed.

https://support.apple.com/en-us/HT201372

This is as much help that can be provided without knowing the exact details.

Original Apple SSD installed or is it a third party SSD?

When you provide error messages we need to know which version of the macOS installer you are using.

Exact details are very important since we cannot see what is happening.

Your drive may not be showing because it is an nVME drives, for which support did not appear until 10.13 and you were running 10.15.

Mavericks on the flash drive is too old to see nVME drives as drives.

Got a good Internet connection? Use Recovery to get more recent tools:

How to reinstall macOS from macOS Recovery - Apple Support

EDIT: HWTech's most recent post was not visible when I started composing. I did not intend to contradict anything they said.

As @Grant Bennet-Alder mentions you have a standard M.2 NVMe SSD.

What OS was on this system before it was erased? You should be able to reinstall any macOS between macOS 10.13 to the OS which was installed previously (in theory). While booting into Recovery Mode using Command + R should boot the installer for the last OS installed on this laptop it does not always do so.

If this happens you can try booting the Catalina installer with Internet Recovery Mode using Command + Option + R. If Catalina was not previously installed, then this option may not work since the installer will want to install the latest system firmware update which may require an original Apple PCIe SSD to be installed. Unfortunately the information/details about the rules/requirements are not completely known since it seems to vary between different systems.

As a last resort you can create a bootable macOS USB installer using these instructions:

https://support.apple.com/en-us/HT201372

macOS 10.13 High Sierra is likely a safe bet to choose since this is the oldest version of macOS that would work with a third party NVMe SSD. You can try Mojave or Catalina, but if you get the "firmware" error message, then it means either the SSD is not properly erased or the installer requires an original Apple PCIe SSD to be installed internally (and properly erased) so the new system firmware can be installed. After which you should be able to install that version of macOS to the third party SSD.

FYI, Apple has made life very difficult and complicated for anyone using a third party PCIe SSD in an Apple product especially when upgrading to a new version of macOS. Apple makes several slightly different versions of their proprietary PCIe SSDs so you must make sure to use the proper one made for your exact model laptop if you decide to temporarily use an Apple SSD to update this laptop.

If that is still the only drive available after a restart, then your drive died while you were erasing it. You got out just in time.

Or maybe it did not get re-inserted properly.

Internet Recovery creates more than 25 RAM disks to hold temporary items. No disk of any description is required or used for Internet Recovery to get you Disk Utility.

just searching that part number gets hits for an nVME drive, not the older ACHI type.