Even looking at it from that angle, Headmasters wins in terms of leadership transitions due to its story elements!

Optimus resumed the leadership and stayed on without transitioning to anyone else in Rebirth.

Headmasters had Convoy (Optimus) as the initial leader, but he sacrificed himself and leadership took a step back to Rodimus, who kept it until Cybertron was destroyed and then he passed it to Fortress (Cerebros), but it was more of a title transition cause Rodimus kept the Matrix! That's a noteworthy trend in the Japanese Continuity... the Cybertron (Autobot) "Supreme Commander" doesn't necessarily carry the Matrix, but they carry a title and primary leadership roles. And none of that begins to cover the power play between Galvatron and Scorponok!

We also never said that Rebirth DIDN'T have Headmasters! The story and the origins are what make the two incompatible with each other! The US also has more than one origin myth for the Headmasters cause both Rebirth and the Headmasters cartoon are incompatible story-wise with Marvel US (and by default, Marvel UK)!

Where does Trans Formers Prime take place in continuity?

It's its own continuity. It's part of the Aligned continuity, encompassing Prime, Robots In Disguise (2015), and technically two video games: War for Cybertron and Fall of Cybertron. The video games are largely intended to be prequels to Prime, but offer just enough contradictions to be considered nebulously canonical.

The Aligned continuity is one of the funniest ironic names in Transformers in my opinion

You're not wrong! I love that Hasbro made up this huge binder of background details, and almost every participating studio only looked at maybe 25% of it. Huge entries on the Wiki trying to make sense of completely different scenes between games and books and TV shows, until eventually everyone went They're Not One Story.

I'll quote part of my post from last page

"After that, anything goes pretty much. Almost every new series since Cybertron has been reboot after reboot. Only exception is what's known as the Alligned continuity family of Prime, Rescue Bots (Academy) and Robots in Disguise (2015). Prime and Rescue Bots take place at the same time, but Rescue Bots was aimed at a much younger audience, and it's plot kept separate from Prime. Robots in Disguise (15) is a sequel to Prime, and takes place at the same time as Rescue Bots Academy, a sequel to Rescue Bots."

Timeline wise I started with The War For Cybertron. G1 will be next. War For Cybertron is the origin story of Trans Formers. I'll watch Beast Wars after the winter break In the spring I should be starting Super God Master Force. 132 episodes after G1 and Headmasters.

If you're referring to the Netflix War for Cybertron series that's also not at all true. Have you been reading the info we've been giving you? TokuKnight already explained that the WFC trilogy is it's own thing

I was reading the book Trilogy a little bit and it was the first battle with the Autobots and Deceptions. How after that book trilogy is War For Cybertron?

Ah, sorry for the misunderstanding. If you're referring to thr trilogy starting with Exodus, those are also a separate thing from G1. The first book is a loose adaptation of the War for Cybertron video game, which was inspired by G1 but took place in the aforementioned Alligned continuity. The second and third books tell an original story that leads into the lore of that universe that's hinted at in Prime and significantly covered in the Covenant of Primus book. The Netflix War for Cybertron is another separate thing inspired by the G1 Cartoon but not directly compatible with it. The Netflix War For Cybertron does take place within the greater G1 family of universes though, like the IDW comics or the 80s Marvel comics.

Here, this page on TFWiki, the actual good Transformers Wikipedia should explain things