I have a friend who left her baby for 3 weeks at a similar age.
He was well cared for by the grandparents, who he already knew.
But honestly he cried pretty much all the time.
They lived near me and I often chatted to the grandparents while they were walking him up and down in the buggy trying to get him to settle.
He pretty much cried till he was exhausted, went to sleep, woke up and cried more.
It was very upsetting for all involved.
When she got home he immediately wanted cuddles etc with her - but he then had horrible separation anxiety for months. He would literally scream and cry if she put him down in a bouncy chair while she was right beside him.
I once held him for two mins at baby club while she went to the loo, and he was distraught.
He’s 3 now and still quite a clingy and anxious child. Obviously no way to kno I whether the separation caused that, but she constantly worries that it did.
She told me last month that it was the single biggest mistake of her life. She regrets it everyday. She’s pregnant again and says she wouldn’t dream of going away while this baby is so young.
So based on that, pls don’t do this.