[One (M8) Original Android Development] CutGlass:
Right this is a big one and yielded some very unexpected results. First the set up. Full Twrp backup to the SD card and then copied onto a PC for safety. Two cards one Lexar I use daily as f2fs and extended app storage, one rubbish Toshiba straight out of the packet. (photo 1)

You will see why I had to take photos in a minute. Phone shut down, boot into twrp, factory rest, put on LineageOS (LOS) from 31st, install, reboot, fill out various details (all with SD card slot empty). Boots into LOS, try to take a screenshot notice that something odd is happening, claims limited storage space. Pop in New out of the box sdcard into slot, try to take another screenshot (failed) so have a look in settings > storage.

Out of the box the toshiba card has a supported filesystem but still refuses to take screenshots (photo 2). Hence why these are photographs of the screen not screenshots.

Very Odd thing

A brand new system formatted without the Lexar card in has "remembered" it's existence. Just to be entirely sure that I have not made a mistake like wiping without taking the card out, I do a factory reset again. Same results, the f2fs is remembered. I don't want to go advanced and format the partitions in case of data loss if there is some persistence I doubt the validity of my PC backup.

After having done the full reboot, enter details etc... I take the SD card and format it as Apple Journaled with GUID boot record, as I happen to have a USB adaptor by that computer. I believe that any unrecognised file system will work like NTFS on a windows machine. Linux you might need to get creative. Pop the sd card into the phone slot and as predicted it brings up the "wizard" and note the top status bar now has an SD card icon. (picture 3) Previously in the failed screenshot there was no sdcard message as it had recognised the out of the box card.

Set up internal SD Card, use as internal storage option is visible and I choose it (picture 3 and 4). Note that Internal storage (F2FS) claims to be device specific in picture 4, (SD card will only work in this device), so I'm not betting on an externally formatted F2FS card especially with the persistence.

Picture 5 - told you the toshiba 64Gb card was rubbish, but it plugs away.

Picture 6 - success and now the option to move App Data, so is formatted as F2FS

Picture 7 - confirmation in storage settings that even though the Lexar was remembered the new device is inserted, read, and not eject button for portable storage.

Picture 8 - further confirmation that the new card is F2FS and can store Apps.

Picture 9 - because of concerns about the persistence for the Lexar I chose to format the new F2FS card back to portable storage and then unmount it before taking it out and booting into recovery, factory reset etc... turn phone off, put in Old F2FS card, restore from backup. And finally I have a lot of storage being wasted because I transferred the backup using ADB just in case I ran into problems with not recognising the original Lexar card (I didn't) Now I have to clean up my filesystem.

So fundamentally what I initially described worked across two differing 64Gb cards one of which is "unloved" by the system, put an SD card in an unrecognisable format and you should have the option to format it as f2fs on device. The persistence of the Lexar Card was a surprise so I would recommend not just a factory reset wipe but a format (without any SD card in) if my methodology doesn't work, and possibly the Lexar would need to be formatted from scratch as the warning does say that the SD card is device specific (back to picture 4).