Could be a challenging read

I have just finished I See You by Clare Mackintosh.
I forgot to post a picture when I started it.
It was a gripping fast paced read but had a few plot holes in my opinion.
I have now moved on to the tattooist of Auschwitz. I think this may be an altogether different kettle if fish.
It was recommended by a friend on Facebook and as I love all things 2nd World war I thought I would give it a go. I am not far in and I already love it.
I think it might be a tough read in places as it is based on a true story but I really liked the main character immediately which is always a good sign for me when reading a book or watching a film or TV series.