T5 you have a dynasty with multiple family members who can act as building managers and not just one president. It also has a more drawn out campaign that carries the story through multiple era's and back again, and not just a bunch of stand alone scenarios.

Basically it depends, if you're just a sandbox player you're missing most of what these games offer anyway and T5 won't feel much different to you.

If you actually play the scenarios and campaigns, T5 is probably the most unique story and family dynamics.

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Functionally it's also interesting to see how the series developed, though that might mean more if you've actually played 1, 2, 3 and 4, not just 4 and 6.

T1 is the only game from the original developer (Poptop Software). It as mainly a dictator sim with building elements. T2 is from another developer, it's a reskin with the same mechanics, but you're a pirate king.

T3 is from yet another developer: Haemimont Games. They took the same engine, modernized it (for its time) and made their own version of T1. This same developer then went on to make T4 on top of T3 which became more of a parody of a dictator sim and focused more on the humor. And then there's T5, the pinnacle of Haemimont Games working on the series. Unlike the previous 4 games that had all been built on the same engine, Haemimont Games made their own custom engine, a much longer story and tried to reimagine the series as a dynasty simulator.

So, T4 is the last of the games built in the original engine and T5 is a reimagining of the series from the developer that made the most games in the series (but not the original)

And then there's T6, yet another new developer (Limbic) and another new engine (built from scratch in Unreal) it's as you can see a bit of a mashup of borrowed elements from T4 and T5. It was a buggy mess until Limbic stopped working on it and DLC development was taken over by yet another developer Realm Forge who fixed the game as best they could and well, you asked about T5 so I'll stop there.

I guess it just depends on how into the series you are. With 6 games they all offer something slightly different from a variety of different developers. Though you might not appreciate the differences much if you don't play them in order and actually see how the campaigns and changes developed through the years to where it is now.

Starting From Scratch: Haemimont Games’ Tropico 5 Postmortem:
https://www.haemimontgames.com/starting-from-scratch-haemimont-games-tropico-5-postmortem/

I've played them all and there's pieces I like from each

yes

Im my opinion 5 is better then 6 and about equal or just a little behind 4. But yea 6 is weak.