Calm down.
You will be likely to be accused of awful posts, by posting thus.😁
My dear close friend of nearly 50 years having been subject to a similar type of SM, makes it definitely personal to me.
The grief and loss doesn't dissipate.
I know this because I have listened to my friend for so many decades, .......yes decades, and she is a massive believer in therapy and self help.
This pain, grief, loss, emptiness, doesn't dissipate.
It remains.
My friend is a outwardly a hugely successful woman, very publicly noted, lauded, awarded.
But with me, .....privately, .......she is always the confused 10 year old that suddenly lost her wonderful mother, who was replaced 2 years later, by a woman who inexplicably actively disliked her, .......and felt very threatened by her, ......and her fathers love for his lovely ex wife.
My dear friend has paid a huge, quiet, private, price for this, her whole life.
Her father definitely knew his knew wife was a dud,......I witnessed it, in their home ...but he said nothing.
This is indeed very personal to me.
The impact of the wrong step parent after a bereavement is simply enormous.
My husband also lost his mother very suddenly ,and his father grieved her hugely,.........neglected my husband in his grief, but bless him he never inflicted an awful step parent on him.
Since we are together 30+ years, and he has become close to my dear friend, he quickly developed even more respect and regard for his much loved late father.
He recognises her additional grief to his, and appreciates that his dear dad at least never inflicted some woman on him that would have only compounded his grief.
I really am hoping the OP steps up.