I'm having a difficult time installing Debian 12 on a 3 drive system. 2 6 TB drives and 1 2 TB drive. I want the 2 6tb drives to be part of a multimedia LVM and I want it encrypted.

When doing this, the installation says I need to encrypt swap however, automatic partitioning didn't create a swap partition. So I had to delete the 2T partition, create an efi partition because it complained about that and I chose to create the encryption for all 3 partitions at once. I also tried by first creating the LVM for multimedia and encrypting that and swap but still having a problem booting.

It asks for the password and depending on how I set it up, either multimedia passes but swap does not and it puts me in a emergency mode loop or it doesn't accept the password and puts me in an emergency mode loop.

This is the error message I get after the install completes.

I'm taking a shot in the dark here, but if I understand what you want, roughly:

You have 3 physical disks, lets call them /dev/sda, /dev/sdb, and /dev/sdc for simplicity -
- /dev/sda is a 2TB drive that I'm assuming you want to install the base system on
- /dev/sdb and /dev/sdc are matching 6TB drives that you want in some sort of LVM (how configured/why/etc) for additional storage, and also wanat it encrypted

Some thoughts: if you don't care about the base system being encrypted (you don't specify and I'm not going to presume to tell you how to setup your box), just install Debian as normal on the 2TB and then configure the encrypted volume from within the working system (much easier to do this than in the installer), and configure auto-decrypt/auto-mount if wanted there too (you can do almost all of this from within GUI in GNOME Disks if you're setting up a GUI on this system that is, except for the initial LVM configuration, the rough steps are to create the LVM out of the two PVs and then you can configure it in Disks with encryption and mount options very easily with step-thru menus).

Alternatively, depending on why/how you intend to use the LVM, it may be also worth considering mdadm or a union mount for those two drives, which have different possibilities for configuration, but again I'd do this post-install

If you want the system drive also encrypted, I would only bother with that at setup (the trend line here is: leave all the secondary disks until after you have a booting system to make life easier), and you can probably find guides online for setting up encrypted Debian install - I honestly don't know what the Debian installer itself offers these days for FDE (Full Disk Encryption), but if you aren't explicitly wedded to Debian, a number of Debian-based distros (like Ubuntu and Sparky) offer essentially 'one click' FDE in their installers, and will setup the associated LUKS/LVM provisioning on the disk (the Debian 12 installer may offer this also).

As far as swap - setting up a separate encrypted partition will be obnoxious (or more broadly: doing this without LVM for FDE will be obnoxious), the most easy way to do this is to (after you have a booting FDE install on the system) set a swapfile on the / disk (or wherever you want it actually), otherwise you can do it the 'Ubuntu way' (as in, how their installer will automatically configure things) and create a second LV on the / disk vg (e.g. /dev/sda from above example), to use Ubuntu's naming (because it will make sense) you will have a vg called something like vgubuntu, and then within it will have two LVs, one will vgubuntu/root and one will be vgubuntu/swap, and default makes swap 1GB. This is less flexible IMO because if you need to resize swap you have to resize the LV which may mean resizing both LVs against the vg, and then resizing the file system, which isn't suggested against a mounted fs (and if that mounted fs happens to be root, you see where this is going...), whereas with swapfile you can just instance a second swapfile and enable it if you need more capacity at some point in the future.

Finally if it isn't clear, I would also probably 'start over' with this install from a blank slate.