if there is a direct one pairing ending I'd be very shocked if it's anyone but geordo. If it's harem/multi-ending or ambiguous- that's a different story.

there's two main reasons.

because in JP where they make the most money off it, katarina and geordo are the number one pairing by far. Like Keith and Katarina are the only ones close to second place. the rest are pretty distant. Like the studio gave out free marketing posters to anyone who came in at one of the big anime sales chains 3/5 were of geordo and katarina, one was of keith and katarina and the last one was katarina by herself. They also have released special short stories in several special editions of the LN almost all are Geordo related.

Hamefura currently has no Yuri tags in marketing, not even shoujo-ai and is published under an exclusively shoujo and romance publishing house. They also are adapting hamefura into a Visual Novel by Otomate a company which is one of the most prolific for otome games has only done one Yuri route ever in their over 20 year history of making games. The preview came out for the game already and the girls are not playable routes and are supporting cast.

Based on these marketing moves that have been approved by the studio, the publishing house and the author, it would be a very bold and sudden move.

And a move with a lot of backlash in Japan considering the yuri pairings are no where near as popular as in the west.

However I think we're at least 3 years off minimum from any pairing decision so that's not to say that all couldn't change based on reaction to anime and the fanbase but right now he has the best odds by a longshot.