Well, for those wanting a real answer, Steven Caple Jr has one: Continuity in this franchise DOES NOT MATTER. Even though this is all the same film series, the events will not match up, because each movie or series of movies focuses on their own thing. They should instead be treated as stand-alones. And not just the new films, but the previous Bay films too. Below is the transcript of that part of the interview, within the Empire Podcast Spoiler Special with Steven Caple Jr, where continuity is discussed.
Interviewer: In terms of the continuity of the franchise, are you worried about matching it up with the first Bay film, which suggests that Optimus has never been to earth before…
Caple Jr: … But now it’s kinda broken already. For me, I’m not like fully worried about it. There are things I would love to stay within that line, but at a certain point, we all know it, Bay has admitted it, I had certain conversations with him like, in terms of tracking the storyline by movie 3, 4 and 5 (5 specifically i would say), now it’s kinda like …
Interviewer: … they were freestyling it
Caple Jr: They were freestyling. Unicron is planet earth, it was things like that. Cool conceptually but that’s a lot to unravel and will we ever see Unicron? Cause now it’s Earth. Probably a reason why they stopped right there. So like, for me, I’m not worried about it, it’s about what’s best for the movie. For me, I have my classics. We got movie 1 with Sam witwicky, it’s a classic. Then we got 3, some of the best action I’ve seen in any movie, best Transformers battles, like it was really good. Those are the movies, they’re like stand-alones. For us, we just make sure about our story and if it tracks through each one [we make]. If we try to hold ourselves to what another storyline/ timeline was, we’d definitely be in trouble. Cause at a certain point, I don’t think anyone knew exactly where they were going with 4 and 5.
What you just read is the new official take on the matter of continuity: that it does not matter. You'll see that the word reboot is not uttered because that's not what anyone making these films want to convey either. This film, Bumblebee, AOE, TLK, and the initial trilogy are all their own stories within the same franchise, but with no need to connect perfectly to eachother. They are all constant (soft) reboots in their own way, if you want to see it that way, but also all (soft) reboots of Bayverse. So the Bayverse is far from dead, it is instead fragmented, and anything can happen from here on out. So have fun with that take.