Baby not settling in night

[Jjjjjjs]

Our 8 month old has become really difficult to settle in the cot during the night. She has always been a terrible sleeper (waking at least 5 times a night) and we have only managed to get her to sleep in her cot for the last 4 weeks. But now one time she wakes in the night (varying times) she will take up to 3h to settle back down in her cot.
Anyone got any tips for trying to settle her?
I assume the issues are just linked to a sleep regression/ leap.

4 weeks ago was she cosleeping in your bed? In which case it's just too soon to expect fully independent sleep. The change from cosleeping to independent sleep is a very long journey.

4 weeks ago was she in a crib in your room? In which case I would have made the transition from crib to cot in your bedroom rather than own room so that the level of change being dealt with all at the same time was less.

How does she get to sleep?

She was cosleeping with us and she is now in a cot in our room next to our bed (but yep maybe we are expecting a bit much too soon!). She goes to sleep at bed time on her own- I put her in her bed and say goodnight and leave the room and she just goes to sleep

She just seems to have become a lot worse at settling over the last few days, before that we could just plonk her down after getting her back to sleep and she would settle straight away