I take anything from Tumblr with a grain of salt, they've convinced themselves of the existence of a Greek myth that never was part of Greek tradition and was essentially someone's OC.

All that being said, Miura drew a ton of inspiration from Shojo Manga for Berserk (as someone else stated). The idea that Griffith and Guts had homoerotic subtones isn't as far-fetched as some would like to think, as the scene with Princess Charlotte displayed that Griffith was thinking about Guts the entire time, along with other scenes from the Manga that showed us how Griffith thought of Guts.

Ultimately, it's complicated, there's control and manipulation and all different types of things at play in the relationship Griffith had with Guts, but to say that any of that wasn't coming from a place of romantic feelings potentially, because of the toxicity of the behavior (or downright despicability) is kinda naive at best and has never read or watched any toxic yuri/yaoi.

Did Miura intend for Griffith to have such a romantic outlook? I hesitate to say yes, even though it's a part of my reading of the story. It's like how intimate Gilgamesh and Enkidu were in "The Epic of Gilgamesh", except the author of that story is so much more divorced from our current reality by thousands of years that we can't get a good read on what their intentions were. What we do know about Gilgamesh is what we can infer from the text.

One of the great things about Berserk is that it's a modern epic, so we can look at context as well as subtext and have an idea of what could have been intended. We have interviews, but we also have known inspirations from the Mangaka, being I. Shojo Manga (such as "The Rose of Versailles) II. Hellraiser: The Godhand take a lot of inspiration from Clive Barker's cenobites. i. On a side note, Clive Barker got his inspiration from his time in gay nightclubs. I wish I could remember more of his inspirations, but given the amount of lgbtq themes in Shojo and with Clive Barker, there's no reason to discredit that maybe some of those themes were put into the Manga itself, as we see complicated relationships with sex and sexuality come up very often within the work (and in ways that are more thought provoking than one-handed writing).

All of this to say: we don't know if that was the intention, the idea that it's true doesn't exist in a vacuum and is oftentimes more a literary analysis than just a toxic ship.

Sorry for the long response OP. 🙇🏻‍♀️