For what it's worth(not much) On OpenBSD swap is always encrypted, With or without full-disk encryption. I don't know why linux always has to make the easy things hard.

Swap files are very fragile if you are using hibernation. For FDE I prefer LVM-over-LUKS and a dedicate partition

How so? It's a one time setup procedure of only a few steps to create a tiny "protective" ext4 (or whatever) partition at the front. Thereafter you configure crypttab to mount the partition via UUID with an offset and key. If you don't need to hibernate you can read the key from /dev/urandom.