La Sirena problem in season 3 of Star Trek Picard

[Mondragon]

It's was establish Picard's new body maintained a regular human lifespan.
So it's really going to be if the actor wants to stay on longer.

La Sirena problem in season 3... with the nature of La Sirena the defining challenge if the show wants to go for the full 5-7 seasons

As for the rest of the crew continuing in some capacity in a hypothetical spin-off show post Picard. ...? It's really wouldn't be a narrative or character problem.
You say:

There also needs to be a good reason for the characters to not go there seperate ways.

Reason would be Picard inadvertently put together this broken and adrift group outside the purview of Starfleet, and got them all doing what they were good at, despite Starfellet having failed them. Where they become a functioning crew and family.
That is reason to stick together, and keep doing what they are doing, and living up to the ideals and legacy of Picard, who brought them together, and keep functioning and having adventures as an independent crew on La Sirena.

If the threads premise is a hypothetical a spin-off show where they are working for Strafleet, then that works too.
You say...

Much of the problems discovered by the Sirena are now in the hands of Starfleet...

The key obvoius difference between La Sirena and a Starfleet vessel is that it is an ad hoc collection of a task force not a Starfleet or professional vessel, has alot less powers then a Starfleet vessel to deal with problems...

If Starfleet recognizes how well they worked together, and they are assigned their own Starfleet vessel:

-Rios, a former Starfleet commander, ExO on the USS ibn Majid, heavy cruiser.
Could (and should be after the truth came out) reinstated into Satrfleet, and made commander of a new vessel.
-Raffi Musikera who was lieutenant commander, under Admiral Picard, the same can also be reinstated, and made part of the crew.
-Depending on their mission objectives Seven of Nine Annika Hansen would potentially join them.
-Dr. Soji Asha as science officer.
- and Dr. Agnes Jurati as the ships doctor.
- The only real loose end, who wasn't involved and didn't came up through the Federation or Starfleet is Elnor, who they can take on as cadet in his first field mission, as part of security I would imagine, and would coincide with the Qowat Milat narative of wanting him to experience the world.

And finally La Sirena itself can easily be re-purposed as the main Shuttle/Runabout for their new Starship - Picard (or any other name, it really wouldn't need to be that.)

Point is either way, there is both narrative and character justification for them to continue together as a crew, beyond Picard, if they wanted.

 

[Mondragon]

If the threads premise is a hypothetical a spin-off show where they are working for Strafleet, then that works too.
If Starfleet recognizes how well they worked together, and they are assigned their own Starfleet vessel:

-Rios, a former Starfleet commander, ExO on the USS ibn Majid, heavy cruiser.
Could (and should be after the truth came out) reinstated into Satrfleet, and made commander of a new vessel.

-Raffi Musikera who was lieutenant commander, under Admiral Picard, the same can also be reinstated, and made part of the crew.

-Depending on their mission objectives Seven of Nine Annika Hansen would potentially join them.

-Dr. Soji Asha as science officer.

- and Dr. Agnes Jurati as the ships doctor.

- The only real loose end, who wasn't involved and didn't came up through the Federation or Starfleet is Elnor, who they can take on as cadet in his first field mission, as part of security I would imagine, and would coincide with the Qowat Milat narative of wanting him to experience the world.

And finally La Sirena itself can easily be re-purposed as the main Shuttle/Runabout for their new Starship - Picard (or any other name, it really wouldn't need to be that.)

Point is either way, there is both narrative and character justification for them to continue together as a crew, beyond Picard, if they wanted.

Pretty much...

 

[TimeIsAPredator]

I'de love a show post Picard with Capt. Rios, Cdr. Rafi, chief science Agnes, and finally give 7 a SF uniform

 

[Kamen Rider Blade]

In what starts as the prime time-line, after Seven joins the Stargazer at the anomaly, Rios says - What the hell have you done to my ship?
Seven - Correction my ship.
Rios - Look after her I said.

So the assumption from him seems like it was a lone.

What I can't tell is, next time we Seven she's already on board the Stargazer if she transported, and La Sirena is just drifting along side . Or If La Sirena docs on-board the Stargazer?
They shows Picard's shuttle docking.
And she meets Picard in the Docking Bay, However as far as I can tell they didn't show La Sirena docked ?

I thought the La Sirena was just following the StarGazer?