JLoGukA The Samsung M.2 NVMe is in the computer, and the Seagate Barracuda 1 Tb ST1000LM049 SATA is NOT in the computer. You are trying to install to the Samsung M.2 NVMe using a Solus 4.1 Live USB. Gparted can see the Samsung. The Solus Live USB works when you boot, but when you try to install Solus 4.1 off the live USB, the Solus installer can't find the Samsung. You are attempting a UEFI/EFI install according to Solus instructions (Secure Boot off, UEFI install, ACHI/RAID settings and so on). Solus 4 installs, but Solus 4.1 does not. Is that all correct?
Two questions:
(1) When you go into BIOS (F2 while booting on Dell, but I don't know what it is the HP pre-boot call is) does the UEFI recognize the Samsung? I'm guessing that it does.
(2) With the Solus Live USB up and running, open the File Manager, click on "Other Locations" and look down the list that opens. Can you see the Samsung on that list (it should read something like "254 GB volume" and be identified with a /dev/sda3 designation). I don't have a guess here, but on both my Solus computers, the Solus Live USB can see /dev/sda3 on the NVMe SSD drive.
It is the answer to (2) that I am most interested in. If the Solus Live USB sees the Samsung NVMe drive in File Manager, then I have no idea why it doesn't see it during the install. If the Solus Live USB doesn't see the Samsung NVMe drive in File Manager "Other Locations", I'm baffled, but then at least we have a starting point.
I really doubt that TPM of the other things you disabled (other than Secure Boot, which must be disabled in order to run the Solus Live USB and subsequently install) are likely culprits. I have TPM enabled on both my Solus computers, but I'm not familiar with Intel Software Guard Extensions, so I don't know about that as a potential issue.
I have a stray thought that might be -- or, more likely isn't -- relevant. I'm not particularly knowledgeable about HP computers, but about a year ago I installed three HP ELITEDESK MINI PC's at the small railroad museum where I volunteer as the IT guy. The computers had been set up by a QuickBooks/QuickbooksPOS vendor, so all I had to do was hook them up, start them up, get them on the network and hook up printers, scanners and other peripherals. Other than update Windows 10 and clear out all the bloatware that Microsoft and HP love to install, I didn't have to muck around in them. But I notice that on every boot cycle, just when the HP logo showed up, there was a message about "HP Sure Start" or something like that. I didn't know what it was, so I called the vendor and asked what it was and how to get rid of it. The vendor told me that it was an HP pre-boot process to protect the boot and that I couldn't get rid of it. I doubt that this (or one of the other wonderful things that HP loves to put on computers) is causing the problem, but it might be worth a Google if that or something like it is showing up during the boot process on your computer.
This absolutely baffles me. Something is blocking (protecting) the Samsung during the installation process in 4.1, but didn't in 4. It has to be something in the HP pre-boot processes or something in conflict with the 5.4 kernel. It isn't impossible that there is something going on with NVMe, but no NVMe issues have been reported with kernel 5.4. so it is real unlikely.
Yikes! I love mysteries, but you must be tearing your hair out.
I'm hoping that someone with more expertise that I have will read this, and jump in.