I'm using bcache to have a HDD+SSD setup (cached HDD using SSD, which is useful in the current days). As I only have HDD+SSD in this system, I put the root inside a bcache backing partition (that's a bit convoluted process to setup this, i.e copying
/var
/var
btrfs partition into a bcache device)
However, bazzite doesn't provide the bcache driver (and bcache-tools) by default, so it doesn't work properly unless I enable initramfs regeneration (and add bcache-tools package); but doing that breaks updates (well, the SteamOS update button doesn't work anymore).
What can I do, alternatively, I can try having bazzite on a part of SSD, and the rest being bcache cache; and the HDD being used separately, but that also has it's own set of problems and limitations (especially since the SSD is not incredibly large).