Installing Fedora 33 alongside other data on an nvme

I have an 1 TB nvme m,2SSD onto which I want to have Fedora 33 along side other data. I preformatted some partitions vis:
500meg fat32, flagged boot,esp for /boot/efi
1 gig ext4 partition for /boot
100gig btrfs for / and all subdirectories that install under /
800+ gigs reserved for other use.

Anaconda refuses to touch the 100gig btrfs partition. Any suggestions. Do I change the partition format to deleted, ext4? How do I proceed?

Anaconda offers custom. same issue.

Duplicate of