@dhojnik Raspberry Pi 4 (8GB) with 2x Seagate Barracuda 2.5 5400 (ST5000LM000-2AN170) and 1x Seagate BarraCuda 120 SSD (ZA2000CM10003) mounted within an Argon EON case running Ubuntu 22.04.2 LTS (GNU/Linux 5.15.0-1033-raspi aarch64) which is extremely stable – only requiring rebooting after applying Linux system updates (e.g. kernel).
I don’t currently have RAID configuration enabled but take a look a the following thread: SATA Connector Mounting Read-Only - #4 by NHHiker
I would recommend taking a close look at your system logs and then experiment with a maximum of 3 drives as it seems that the SATA board may not actually be able to handle 4 ST5000LM000-2AN170 simultaneously.