It looks like there are some regressions in Debian for linux-image-4.18.0-1-amd64 compared to linux-image-4.17.0-3-amd64 for for Ryzen 5 2400g.
In the older version of kernel ACPI sleep works and and nothing crashes wheres in 4.18.0-1 there are periodical crashes and the system refuses to wake up.
I'll submit a bug report, but without a stack trace it's everyone's guess about how useful it would be 🤷