Although it may or may not mean anything, here's something that people seemed to miss with this manga: the entire story is spread almost completely throughout 2019, meaning the ending was probably set either right around the end of that year or shortly after turning over to 2020 - IRL that was around the same time COVID-19 was starting to spread globally.
Now whether the author would have incorporated the pandemic into the story if it kept going is up for speculation. But considering the realistic approach to the story - if the author did do so, going by Hana's character and how things always seem to go wrong for her right after things were going well, i wouldn't be surprised if her newly shared life with Takaya would turn into complete WFH/quarantine chaos right after the happy point at which the story abruptly ended.
So while the ending did leave a lot to be desired, it may have been for the best that this manga ended where it did.