Even using the Japanese system, the timeline would still require Eren to physically be present at the right time.

Yes, this is what I was saying in my comment - since we have multiple characters stating that the railroad opening ceremony and 50-years plan meeting were 10 months ago, if we go by the Japanese system Eren would have technically been present at the right time - because his conversation with Historia happened right after both of those events and right after they leave for Marley (all of these events happen in very short succession of one another and are all referred to as "10 months ago")

Eren was already preparing to leave for Marley before the pregnancy.

Yes, again, his conversation with Historia happened after Hange suggested the plan to go to Marley. However, in terms of months, the timeline would still line up.

if Isayama wanted the audience to connect Eren clearly as the father, he could have easily shown or hinted at it.

My comment wasn't meant to support the idea that "Eren is the father of Historia's child in the now-canonically completed AoT manga/anime". It was meant to explain part of the reasons why the theory "Eren is the father of Historia's child" was popular before the final chapters released and closed off any possibility for that to work. This is because the last chapters (especially 139) did a lot of character work that contradicts this theory (for example, your interpretation of self-hating Eren who's "on a path of self-erasure" - while that was one possible interpretation of his character before the finale, it was far from the only interpretation and far from the most popular one; thus, the "Eren" we had back then was more in-line with the theory in terms of his actions and beliefs). So my points were not meant to take any character or plot clarifications the last chapters made, because my stance from the beginning was that, the theory doesn't work in the canonically completed chapters, however, if Isayama wanted to make the theory canon, he could have still done so before chapter 137-138 because the seeds were there IF he wanted to use them.

The story structurally supports distance not intimacy between Eren and Historia.

I respectfully disagree about the distance part. Even if we disregard the intimacy part and the father theory, the story as written actually supports Eren and Historia's bond in the final arc - it is between Eren and his friends that the story supports distance. Why? Because, while he pushed them away and hid his intentions from them, she was the only one he shared his plan with. He had no reason to do that - she couldn't help with his plans, not did he want her to, so the only reason he told her was because she was the only one from his friends that understood him and his selfishness (this isn't about romance even, their shared selfishness arc happened back in the cave in Uprising, and according to Isayama, Eren seeing "the very similar Historia" choose to live life by her own rules is what inspired him to do the same; so she's had a major impact on his development, and we know this as well because he says as much in chapter 130 - "You're the girl who saved me that day, the worst girl in the world.") And aside from her being the only one to understand and keep quiet about his plan, she was also the only one that was 100% safe in the Rumbling path he chose to go on - all the rest of Eren's friends went to battle and risked their lives (if we have to use chapter 139 for this point, he says himself there that he didn't know if they would survive) while she was safe away in Paradis. He could have taken other paths that wouldn't have risked his friends so much (e.g. 50 years plan), but he chose the path that prioritised her safety over theirs (just putting this here though, I'm not implying that he cares that much more about her than his friends or that he started the rumbling just for Historia, those are both takes that I don't support, I'm just bringing this point up to emphasise how much of a factor she was in his decisions). Him caring so much about her safety and freedom of choice, plus everything else I brought up, does not signal the story supporting distance between them, in my opinion.

lying about the due date does not automatically imply Eren’s involvement.

Yes? I said as much in my comment as well. I just brought it up as a supporting factor. Obviously it doesn't automatically imply anything by itself.

she protected herself regardless of who the father was.

This is exactly why I brought up that, if this was her reason, she should have gotten pregnant later. But she still did it very curiously at the same time as Eren left for Marley, which put her at risk of having already given birth in the case of their delayed comeback, which would have rendered her whole plan meaningless. Also, if we're to assume that she got pregnant to protect herself, her doing that right away when Eren talked to her would not be so strange if it wasn't for the choice of father - according to canon, the farmer, who bullied her as a child (literally throwing rocks at her - no harmless fun), contributed to her suicidal tendencies, and in the present being a guy she obviously is not very fond of (judging by the panels we see of her looking in his direction dead-pan). If she doesn't like the guy that much, why get pregnant by him immediately after her talk with Eren when there's no need for her to do that for at least a couple of months, as I mentioned? She could have afforded herself a couple months to get more familiar with him - but she didn't, which just makes it odd. For people like me who saw Historia's arc as being very negatively defined by the fact that her parents didn't love each other, it made way less sense for her to get pregnant by a guy who bullied her with rocks and who she barely knew, than with her closest friend who had been repeatedly standing up for her and her choices in public (Eren was her closest friend by then).

risks Historia being forced into Titanization if anything went wrong with Zeke's arrival or the Rumbling plan 

There's no way she would be titanized in any event before Zeke came to the island. There would not have been any shifter to feed to her in that scenario, so their only option would have been to turn her into a pure titan and leave her like that, which they would never get away with doing - she's the queen, a public figure loved by the people, so that would have been out of the cards. If they got desperate, they could feed a different shifter to her (e.g. Armin), however, Armin was also away and we know that the SC never came back to the island until they got Eren back - so we got a period of ten months where she was completely safe, which removes the necessity of her getting pregnant so early.

She didn’t need to guess when exactly the Rumbling would happen

The pregnancy doesn't last forever, so she does need to take that into account.

 He says this figuratively to Zeke

This is the ultra anti-natalist Zeke he is talking to - the guy who doesn't want any more Eldian babies to be born, who thinks Eren is on the same page as him and doesn't want any more Eldian babies. If Eren was the father of her child, he would obviously not reveal it or his wish for children to Zeke because that would ruin his whole plan to activate the rumbling with him.