It took a few hours but I finished Intermission! Now that I reread the requirements for getting the Leviathan and Ramuh summons in Rebirth, though, it seems like I just needed save files from both parts of Remake and I didn't have to actually beat anything... Whoops!

...Buuuut, even though I installed it remotely while I was at work, I accidentally installed it on my Steam Deck instead of my PC. So now I have to wait for it to download again... I won't be able to play it until morning

I guess that's okay because it gives me time to finish the Intermission DLC for FFVII Remake. I thought I was going to have to miss the Ramuh summon in Rebirth because I hadn't beaten it and that was kind of a bummer. So this snafu is a blessing in disguise, I guess