No, it's more like Power Rangers continuity- it's all one universe (unless acknowledged otherwise), but we don't pay attention to the past.

Continuity doesn't work like that.
I'm not going to accept that Blade takes place in the same universe as OOO just because a movie that wasn't made with either series in mind said so.

just take it like this Before decade there there own worlds all riders after decade share the same world but a diffrent city of the same world that also share the same world as the showa era riders

OK...he travels to the world...something coincidentally happens that he has the skill set to fix...oh and the companions that wander into trouble...heck even Davros called the Doctor the destroyer...

Please do explain how your way of viewing continuity is any more valid than KRX's way.

I treat the SERIES as one world, but given the fact that so many worlds Decade visited were clearly NOT the worlds of their series "Smart Brain high-school?" THOSE worlds were separate continuities.

Kamen Rider Blade.
His presence pretty much confirms that there is no continuity between series, since (Spoiling Blade's ending right here, so if you seriously ever want to watch it, don't look at the spoiler) He became Joker at the end, and let Hajime keep the Spirit card, meaning he can't become a human anymore, yet every appearance of him except during the Blade World arc in Decade has been confirmed to be the Kenzaki Kazuma (Original) Blade, including his (Human, not Joker) appearance at the end of Decade.

And do you not think his friends would try to find a way to get Kazuma out? Besides, given the latest season, if you need a reason as to how Kazuma got out, you could always say, "A Wizard did it." You have three wizards to choose from.

Decade is about dimension hooping. No one ever said that was the real Blade, just a version of Blade that Decade did not meet before. I mean, Black and Black RX weren't the real character, but were played by the same actor. Who's to say Decade ever actually met any of the real Riders other than Den-O and W. That doesn't change anything that happened in Blade nor does it make Blade unable to be in continuity with say OOO.

He abandoned humanity to not risk starting the Battle Fight again. His friends don't know where he is.

At the end of Decade (Around episode 30 or so), Kenzaki appears with the 8 other Heisei Riders (I think Den-O was missing) and straight up says they're the original Riders, who then proceed to attack Decade for sparing the AU Riders (Since their survival means the worlds would start to destroy each other).
This scene is important because Kenzaki Kazuma is the ONLY one of the original Heisei characters to appear untransformed, showing he's completely human.

That completely changes what occurs in Blade, since he's incapable of becoming human anymore.
And the characters in OOO (Or any other series, for that matter) show no signs of remembering when a swarm of demon roach monsters showed up to casually wipe out humanity.