what's happening so far
Thanks for the responses. I am using EaseUS Partition Manager to change the SD card to FAT32 with limited success.
For the first try, I power the phone off and on as I exchange the SD card between the phone and the computer. The phone is off and the card is out, I format it from exfat to FAT32 with EaseUS, immediately eject/safely remove it, put it in the phone, and power the phone on. The phone recognizes it, I power it off, take it out, and store around 10 gigs of music on the card after placing it back into the computer. I safely remove it and put it back into the powered off phone, turn everything on, and it tells me that the SD card is damaged and that I should format it.
For the second try, I dismount the SD card and store around 30 gigs of media on it before putting it back into the phone. The phone begins to chug and slow down, but eventually speeds up and lets me access the data on the SD card as ES File Explorer recognizes it and makes it appear. Curiously enough, there are these new folders in the SD card that weren't there before, prefixed with a Greek "mu" before "apps" or "games." Since they are empty, I delete them, notice that there are more files under "LOST.DIR," and watch a video. I dismount the card again and plug it into the computer whereupon it recognizes all but one of the sub-directories in my video folders, leaving me with two videos to watch, and my music and games are likewise disappeared. I put the card back into the phone and it chugs without getting any faster, and it shows nothing in the same directories, yet the space is somehow being used up according to "data" in the settings. I take out the card and format it.
Third, I format the SD card with the Panasonic software, format it into FAT32 with EaseUS, and put it on the phone to transfer data through the USB cable. The computer eventually tells me that the device got disconnected as it transfers my music into the card and now nothing appears in ES File Explorer. I put the card back into the computer and format it.
I am honestly grateful for any help that I receive here, but I have struggled with this SD card business all day to the point that I am almost nostalgic for my old LG Optimus' ability to accomplish the simple task of recognizing new SD card data. If anyone has a specific and consistently successful way for going about putting their data on a fancy Sandisk, 64 gig, class 10 SD card please feel free to comment.