Uwe , just one important question .
From which direction will you be arriving in La Paz BCS ?
This may be important , and you may already have developed a plan to cover for the problem .
If you are coming by ferry from mainland Mexico then of course you will possess the TVIP . That document must be cancelled before leaving the bike stored for six months .
Left uncancelled the TVIP expires and you will lose the security deposit and have more problems .
There is no way that the Banjercito at the ferry terminal in either of Pichilingue or Topolobampo or Mazatlan will cancel a TVIP . That must always be done at the border , in this case the border at the north into USA ..
If you are coming from the US border intending to go to Mexico by ferry from Baja then you do not need to get the TVIP for Baja California . You will need to get a new FMM at the border in order to get the TVIP at the ferry docks . Both the TVIP and FMM are available at border crossing customs terminals .
I leave untouched the options of getting such documents on-line .
If after the seven months away from the bike you intend to take the ferry to the mainland you will need to get the TVIP at the ferry terminal and to do that you need the tourist card = FMM document which your air-line ticket into Mexico should get you ( but I have never flown into Mexico )
Without first having an FMM in hand the TVIP will not be given to you at the ferry terminal .
For storage you should be able to find a commercial storage facility ( mini bodega ) in La Paz or you may locate some person who is willing to keep it in their garage for less money .
It might make more sense to find a Mexican storage service near the US border , then you will have the FMM and TVIP options both close to hand if you need to get both. The Tijuana airport can get you all the connections to anywhere .
As examples in Mexicali this link
https://simplestorage.mx/nosotros/
in La Paz
https://en.storagelapaz.com/