I use a Raspberry Pi 4 8 Gb as a headless server to run stuff like pihole, nextcloud, wireguard, etc

Ever since I switched from booting and operating from an SD card to an external SSD drive over USB, I find it crashes quite more often (once or twice a week with the SSD vs just me physically crashing into it and unplugging something with the SD card)

What would be the first steps in troubleshooting this issue? Any logs I could check upon boot up to see if I'm having a power issue or if some service is hanging the pi or something like that?