I think the best and most under-appreciated bad robot movie was Hardware[1] (1990). A junked robot gets repaired by scrappers and starts trying to kill them with a poison injection. The nightmare future bad robot stuff won't be this big highly coordinated terminator mass military attack. It will be robots that go from being helpful to deciding they want to kill in a split second because of glitches, malware, or whatever.

[1] https://en.wikipedia.org/wiki/Hardware_(film)