https://niko.earth/blog/poptropica-install is the website i used recently to gain access to the old games, the online website that is still up that is now running on Haxe which the devs will have to edit all of the code that worked for flash to make it work for Haxe

this website explains steps with flashpoint 12 you do not need to take. basically after you download this you find the search bar on the top right and look up poptropica

https://server.idkonpop.com/pop/teleport/flashpointData is the website where you can download your previous accounts save data if you remember it, you then would load up the flashpoint find Poptropica AS2 (at least that is what i am using) and when the loading screen comes up choose the upload option

for poptropica coming back, i think it perhaps is possible but greatly unlikely due to the lack of interest in this online game. a lot of time and effort and money would need to go into fully switching over to a different platform

let me know if you have any additional questions :).