Pertaining to standby, autopoweroff, and hibernation mode issues after replacing the factory SSD with a NVMe drive.

You may want to check to see if there is a newer firmware update for your Samsung SSD.

Try unchecking "Put hard disk to sleep when possible" in the Energy Saver System Preferences. Some SSDs don't wake from system sleep properly (or fast enough -- crazy I know). Disabling this setting is also a good idea if TRIM is not enabled.

Also try an SMC reset followed immediately by a PRAM reset (hold the PRAM reset for at least three chimes). Years ago OWC had me perform the back to back SMC/PRAM resets to get their OWC SSD to work properly in a very early MBAir. It sounds crazy, but I can confirm, that performing the resets separately with the laptop booting in between did not work at all, but performing them together did. Maybe it will help your situation.

Apple doesn't care about supporting third party internal hardware. You are using an unsupported configuration with an SSD which was never meant to be used in a Mac. It is hard to say whether the issue is with the SSD, the SSD adapter, or the laptop itself. Apple is unlikely ever to make any changes to fix this issue unless it does so by accident. If you want a supported third party SSD configuration for this laptop, then purchase an SSD made specifically for this laptop. OWC sells and supports their Aura SSDs in this laptop.