Sleeping/self soothe problems

[mom2babygirl]

Hello everyone!
I'm a First time mom to an 8 months +2w old baby girl and I am having trouble with putting her to sleep every single nap.
She is in 2 naps a day and her awake windows are 3 hours (although 4 hours today because of all the crying!)
She was good at self soothing and putting herself to sleep until we went on holidays! 😩😩 when we were on holidays everything changed her naps in the morning started to be longer and lunch naps shorter (it was the other way around with 2h nap at lunch) but because it was a new place and new bed we would put her down asleep for naps and night time.
Now we have been battling ever since we got back. Recently she has been so difficult to go to sleep! Ive tried 2.5h awake window and 3h (which she is on now) but is the same! I have been trying to put her down drowsy and awake and nothing works as she starts crying CRYING!! Today she cried for 45min!!!! In the end I had to go in and calm her down and rock her to sleep (she was sobbing 😭 bless her 💔)
I was so mad and frustrated because I let her cried too long and she was so awake and overtired I feel terrible!!! Am I a bad mom!?? All I wanted to do was cry and crush my head agains the wall 😫😫
She is so good at night! She sleeps through from 6:30/7pm till 6/6:45 am even if she wakes up during the night she goes back to sleep and she was always been good at night.
So I wonder what the benefits are of teaching her to put herself to sleep?? should I just continue to put her to bed asleep?? Should I keep putting her awake??
I could really use your opinions, advise, similar stories, encouragement!!!
I have no family nor friends here so it's always been me and some help from hubby dealing with this! I'm drained 😔
Thanks in advance and sorry for the long post!
3R