What happens to my 5970 Pokemon after I stop paying?

Solution 1:

Fear not! Your Pokémon will not be lost forever.

If you have over 30 Pokémon in Pokémon Home (that being the limit for free accounts), you will lose access to any Pokémon of after the first storage box if you lose your subscription. If you re-subscribe to a premium account, you will have access to all your Pokémon

If you deposit more than 30 Pokémon in your Basic Box in Pokémon HOME while you have the Premium Plan, and your plan then changes to the no-cost Basic Plan, you will not be able to view or withdraw any Pokémon beyond the 30th Pokémon you deposited in your Basic Box.

By re-enrolling in the Premium Plan, you'll be able to view all the information about the additional Pokémon as well as move them out of Pokémon HOME.

Pokemon Support