Oh, right... is this the first time a year has been explicitly shown in a panel? So is 2020 a year ago according to the story? Two years? I would have assumed the story took place around the year of first publication, as is the case with some other manga I've read, which would make that timestamp one year into the future of 2019 (since we've only had one year advancement in-manga so far, even though it's more like four years have passed in the real world as of when this chapter was published, I think?) if we use that logic.
I mean, that's the general assumption with ToniKawa, at least, that it takes place during the year of 2018, whether Hata-sensei has outright said it or not, since the story is framed as taking place during a single year- currently that story has only progressed maybe 5 months so far since the male lead, Nasa's, 18th birthday (and the start of the couple's relationship and marriage on that day) after over 300 chapters -and it'd feel weird for it to take place during a year later than first publication to frame the initial moments with technology depicted and available at that time.
Stories invariably progress slower than the real-time it takes to fully write and publish them. This needs to be accounted for when crafting the story to maintain coherency and continuity, I feel. Introducing something too advanced (because it's new for the author and audience) for the time progression in the story would throw this off, and suddenly you have a single year in the story having tech advancement equivalent to half a decade.
As an example, when both of these stories first published, the iPhone X was the latest main-line model of iPhone, but now we've got the 16. Since these stories have barely progressed a year in-universe, if that, it'd be very strange to have the X treated as the hip new thing at the start of the story, but current-chapters have the 16 showing up in people's hands.
Past a certain point I feel like a 'modern' story needs to be treated like a period piece set in the time when its initial moments were put together, even if it's only a few years ago.