Don't you have a nand backup? WIth hekate you can restore that.
If you don't have one you should make a backup now and build a complete new nand from scratch with the prodinfo and other information from your current borked nand. Since I never had to do this I don't know the exact steps but this should be doable.
In your case I would make a 5.1+ nand from scratch and install autorcm to prevent fuse burning on accident. Then boot a cfw (atmosphere/sxos/rajnx whatever) and call it a day.
For all those things you don't need homebrew loader. But you need a good understanding and you need a pc with hacdiscmount, the firmware files (e.g. from a game dump), files from your current nand (dumped with hekate) and your biskeys from your switch (obtainable via biskeydump) to build a nand.
I already backed up my NAND, as I've also mentioned many times earlier in this thread, as well as the "BOOT" files, which I did by using both of the backup options in Hekate.
I have the 2.1.0 NAND, backed up before I did any kind of homebrew, and on BriccMii, "FUSES: 2" meaning I'm still safe to use that backup. Are you saying, for sure, I can load my NAND directly from Hekate? And if so, how would I go about initiating this? Are "biskeys" the "BOOT" keys I got from the eMMC backup on Hekate?