[1.15.2] How do you store data?

[OneHotEncoder]

I want to keep track of all my portal locations similar to what minecraft does with nether portals and PointOfInterest. I however can't use PointOfInterest since the PointOfInterestType constructor is private (and I want to avoid using access transformers if possible). I've looked into using a world capability (see my previous thread), but I hit a roadblock when realizing that a new ServerWorld instance is created each time I enter the dimension (resetting the capability data). How would I go about storing data without attaching it to anything?

[Novârch]

1 hour ago, OneHotEncoder said:

since the PointOfInterestType constructor is private

Reflection.

[OneHotEncoder]

5 minutes ago, Novârch said:

Reflection.

Couldn't I just as well use access transformers then? Or is there a difference?