If your system boots after a fresh encrypted install (this is full disk encryption incl. boot) and subseqently refuse to boot - then logically something happened in-between …
The question is what
It is possible to hit Esc during boot to hide the loader - perhaps this will hint as to what is going on.
EDIT: just tested the minmal Plasma ISO from manjaro.org.
Full disk encryption - boots like a cheetah - so I am inclined to believe that previous slow decryption when using GRUB boot loader is now in the past.
At least for my test system
$ systemd-analyze
Startup finished in 3.993s (firmware) + 1min 14.876s (loader) + 8.835s (kernel) + 4.298s (userspace) = 1min 32.004s
graphical.target reached after 4.297s in userspace.
$ inxi -SGCmD
System:
Host: cheetah Kernel: 6.2.2-1-MANJARO arch: x86_64 bits: 64
Desktop: KDE Plasma v: 5.27.2 Distro: Manjaro Linux
Memory:
RAM: total: 15.5 GiB used: 1.82 GiB (11.8%)
RAM Report: permissions: Unable to run dmidecode. Root privileges
required.
CPU:
Info: quad core model: Intel Core i7-8550U bits: 64 type: MT MCP cache:
L2: 1024 KiB
Speed (MHz): avg: 1837 min/max: 400/4000 cores: 1: 2000 2: 2000 3: 2000
4: 2000 5: 702 6: 2000 7: 2000 8: 2000
Graphics:
Device-1: Intel UHD Graphics 620 driver: i915 v: kernel
Device-2: Chicony USB2.0 Camera type: USB driver: uvcvideo
Display: x11 server: X.Org v: 21.1.7 driver: X: loaded: modesetting
dri: iris gpu: i915 resolution: 1920x1080~60Hz
API: OpenGL v: 4.6 Mesa 22.3.6 renderer: Mesa Intel UHD Graphics 620 (KBL
GT2)
Drives:
Local Storage: total: 465.76 GiB used: 9.12 GiB (2.0%)
ID-1: /dev/nvme0n1 vendor: Samsung model: SSD 970 EVO Plus 500GB
I have rebooted the system several times now and there is no problems.
Do you any specific reason for 5.4 kernel? - just noted the Puppy 9.5 must be some live system
6.1 is the new LTS.