As safe as any drug that can cause addiction and kill you with an overdose at least.
Relatively speaking, though, you do have a point in that it’s less dangerous than many other drugs people may abuse. Overdose deaths are extremely miniscule in the US at least.
During July 2019–June 2023, a total of 228,668 drug overdose deaths were identified in 45 jurisdictions. Ketamine was detected in 912 (0.4%) overdose deaths, listed as involved in 440 (0.2%) deaths, and was the only substance involved in 24 (0.01%) deaths (Table). A majority of deaths with ketamine detected involved illegally manufactured fentanyls (IMFs) (58.7%), followed by methamphetamine (28.8%) and cocaine (27.2%). Overall, 82.4% of deaths involved either IMFs, methamphetamine, or cocaine. Approximately one third (34.8%) of decedents in whom ketamine was detected were aged 25–34 years, and approximately three quarters were males (71.3%) and non-Hispanic White persons (73.7%).
But as it points out, it’s not unusual for ketamine to be laced with other things that are more dangerous, so if you are obtaining it outside of a proper medical situation, that’s pretty risky.