Split Upper / Lower case + concatenate rows

[p45cal]

see attached.

https://www.youtube.com/channel/UCnxwq2aGJRbjOo_MO54oaHA
https://www.eileenslounge.com/viewtopic.php?f=44&t=40455&p=313035#p313035
https://www.eileenslounge.com/viewtopic.php?f=18&t=40411&p=312889#p312889
https://www.eileenslounge.com/viewtopic.php?f=18&t=40411&p=312886#p312886
https://www.eileenslounge.com/viewtopic.php?f=18&t=40411&p=312752#p312752
https://www.eileenslounge.com/viewtopic.php?f=18&t=40411&p=312734#p312734
https://www.eileenslounge.com/viewtopic.php?f=18&t=40411&p=312727#p312727
https://www.eileenslounge.com/viewtopic.php?f=18&t=40411&p=312724#p312724
https://www.eileenslounge.com/viewtopic.php?f=44&t=40374&p=312535#p312535
https://www.eileenslounge.com/viewtopic.php?p=312533#p312533
https://www.eileenslounge.com/viewtopic.php?f=44&t=40373&p=312499#p312499
https://www.youtube.com/watch?v=jTmVtPHtiTg&lc=Ugy_RiNN_kAqUvZ8W994AaABAg. 9xhyRrsUUOM9xpn-GDkL3o
https://www.youtube.com/watch?v=jTmVtPHtiTg&lc=Ugy_RiNN_kAqUvZ8W994AaABAg
https://www.youtube.com/watch?v=jTmVtPHtiTg&lc=UgzlC5LBazG6SMDP4nl4AaABAg
https://www.youtube.com/watch?v=jTmVtPHtiTg&lc=UgzlC5LBazG6SMDP4nl4AaABAg. 9zYoeePv8sZ9zYqog9KZ5B
https://www.youtube.com/watch?v=jTmVtPHtiTg&lc=Ugy_RiNN_kAqUvZ8W994AaABAg. 9xhyRrsUUOM9zYlZPKdOpm
https://www.youtube.com/channel/UCnxwq2aGJRbjOo_MO54oaHA

[Biespet]

see attached.

super, this looks what I want to see.
I'm new with this, and run into following issue:
I copied my real dataset into column A and B and also added an extra number on the bottom.
Then I change this part of the formula (2 parts) to the last cell number in my dataset. but then I get following error message:

"You cannot change part of an array"

how can I solve this?