Sana IS eternal because of us Sanalites, and not because of themed accounts or annual sadposts about her leaving, but because we carry her through our daily lives, in our hearts and minds and actions. Without invoking concepts of the afterlife and spirituality, that's the closest thing to immortality than any human can hope to achieve.
Despite it being the one year anniversary of my oshi's graduation, I'm not as sad as I thought I'd be. Over the past year, I've made new friends, and re-connected with old ones. I've gained and lost family and shared many happy days and experiences with them. I've discovered new and entertaining vtubers that I've become a regular viewer of. Throughout all of this, I've kept Sana with me, my love for her and my grief over her graduating, but it doesn't hurt the same way it used to half a year ago. I still have that Sana-shaped hole in my heart, and likely always will, but it feels like it's gotten smaller as my love for other people in my life have moved in. I think I've genuinely been healing, and I can owe it to one simple truth:
I'm not alone.
I love you Sana