Sadly not, it's gonna be manual for the time being so if you're thinking about it it's probably worth doing before you have hundreds of subscriptions.
That said, I've gone through it once already on my other account and in the desktop browser it was fine, just involved opening lots of tabs and a bit of copy paste, took about ten minutes for a fairly extensive sub list. But I pity anyone trying to do it on mobile.
I do not have a link so this isn't very helpful but yesterday I saw someone posted that they had made something to do exactly this. I wish I could remember what community I saw it in. You may have to do some digging. Knew I should've saved it...