Where do you think S1 would end?
When Loid meets his target for the very first time?
I said it in () in my post, but I think it will end with the arc where they get the dog.
It ends up being a much bigger deal than expected, and would likely result in the first multi-episode story, and be a solid place to end the first season, and if I recall right it's around 23/24 which will allow 2 chapters per episode, which is a good pace for anime, especially since these are longer chapters than weekly manga. If you wanted to continue a little bit beyond you could, but the stuff that happens right after picks up and recaps the dog arc nicely so would be great to pick up with a year later.
this current arc would actually do more than 2 chapters per episode to get to/through, but it also has had a lot of action panels to get here. Though I could also see them doing a second season and adapting some of the .5 chapters as episodes and stopping before the current arc, and just doing a movie for the current arc instead given the length.
If they did that though.... it wouldn't be until 2024 when I got to see Yor doing boat stuff :(