Sleeping sucks

So daughter is 5 1/2mths. Her sleep has just sucked since the 4mth sleep regression. It’s like it never ended. Either she’s terrible to put to sleep, or she sleeps ok from like 9pm-12am, but then is up over and over again, super restless. I am starting to get to my wits end. My partner works until 9pm most days, so I don’t usually go to bed early. I just don’t know what else to do to help her have a less restless sleep. Please tell me I’m not the only one struggling with this....