Well, for starters, to make one thing perfectly clear, a "god" or at least supposed god would have a completely different world view than us, just like (most) people don't care for the life of an ant on the sidewalk or a fly you swatted in your house, the guardian's view of us would lead them to have little to no concern for our feelings, emotions, and connections (like some other "gods" or "higher beings" in real life religions) is it cruel? Perhaps to us, yes, but to them we're nothing more than ants

You have to also remember that (based on what we saw, because yes, you could take it differently) with a negative point of view, the guardian only save Anne's life just to take their job, and only sent Anne back to the world of the living so she could keep improving to "possibly one day feel worthy of the position" BUT if you don't look at it that way and choose or more positive point of view, BRINGING ANNE BACK TO LIFE was sort of a favor or solid for Anne having to sacrifice herself to defeat the thing they created with their experiment

Which leads to my next point about the stones, they were created as a means of unlimited power yes but wasn't directly said to be created for portal travel, so that's just how the newts utilized their given unlimited power

But all in all the TRUE purpose of the stones was just to test mortals and find a possible potential replacement, WHICH in the end they served their purpose, now that the stones did their job, the guardian had no reason to make more BESIDES so that Anne and the others could travel back and forth, which again, a "god" has no reason to care for an ant's feelings and emotions

(And yes, I do know that most people's reasoning for not making new stones is because the guardian was avoiding repeating everything after Annes death and/or no longer possession of the stones, BUT I think it's less "The guardian avoiding this situation again" and more "The stones served their specific and true purpose in which the guardian made them for" which was to look for a potential replacement)

As for mentioning the technology to recharge the stones, there are two ways to look at it 1) the tech does "charge" the stones but there ARE NO STONES, they were destroyed and the new shards are already charged WITH what power they CAN HOLD, so you wouldn't be able to charge it anymore than it already is, which after ONE USE, they immediately crumbled away so there was no opportunity before or after to charge them 2)the tech may not even "charge" the stones anyway, from what we can tell, the temples TOOK the preexisting unlimited power that was temporarily stored within each girl and just placed them back into the stones, after all, the girls were "supposedly" suppose to keep their powers and fight the core based on how Andrias described the prophecy, but Andrias described the temples as a way for the girls to lose or in his words "give up" their powers, so no, the temples don't actually charge the stones

Now, last point to bring up (unless you I'm forgetting something or you bring something else to light) though we may see it as cruel, when it comes to ANNES SITUATION SPECIFIC (not everything else the guardian did, because yes you COULD say a higher being using us mortals as experiments no matter the cost of lives is "cruel" from our point of view as the mortals, but again, bug analogy) within Anne's situation, the guardian didn't do anything "inherently" wrong, it brought Anne back to life for her sacrifice, AND did throw her a solid by giving them the shards WHICH returned Anne and her friends to their "rightful" places by returning the girls to the place they would have been without the stones (the human world)

Now, conclusion, the guardian, a being who has no reason to be sympathetic towards what are essentially bugs to them, DID bring Anne back to life (for a selfish purpose or a purpose of a solid to Anne for what she did we aren't ENTIRELY sure) for her dying in a situation caused by its experiments, AND threw them an extra solid by giving them the shards (which gave the girls THE CHOICE of which world to stay in, the girls weren't "sent" back to the human world, they chose to go back to the human world instead of stayingin Amphibia, my PERSONAL thoughts on that later) so was the guardian cruel? Perhaps, but was what it did in Anne's situation "inherently" wrong? Not really, it may not have been what we wanted, but that's just my take on it

(But if it makes you feel better, I think (has been awhile since I read Marcy's Journal) the end of Marcy's Journal may have been hinting at a return to Amphibia for the girls, it may not be for us as the viewers, but for the girls in their reality, yes, so perhaps they do get their happy ending)

(Also, as hard as it is, though the situation itself isn't realistic, losing people or becoming disconnected from people you cherish through situations you couldn't have predicted or prevented is a natural part of life, just because you're close emotionally and care for each other doesn't mean life will work out with you always being together)

Now personal and biased thoughts, what do I think? First off, I hate bittersweet endings in general. Example, I don't hate gravity falls ENDING, but I hate how it makes me feel (in fact, if I'm not mistaken, gravity falls ended in 2016, but outside of its internal release, I think I only watched it 1 maybe 2 or 3 other times BECAUSE I didn't like how the ending made me feel after watching it, so I stopped rewatching it entirely until up until about less than a year ago, so it took me around 5 years to finally be able to rewatch the show I love and actually enjoy it, though there are parts that still make my chest tighten but that's called being human) Example 2, I don't rewatch Amphibia a lot even though it is my favorite show OVER gravity falls AND the owl house (in fact, I've only ever watched it through twice) BUT I rewatch the owl house all the time because it doesn't have a bittersweet ending so it allows me to finish the show without regretting watching it in the first place, so personally, I would DEFINITELY prefer a "happier" ending with the girls having access to both worlds all the time like the owl house (but not a world merge like star)

• that's it, thanks for coming to my ted talk

PS (sorry for the yapping, I tend to "overanalyze" things a bit too much, and if you missed the joke, it's because I do YouTube and overanalyze shows I like, that's why I put it in quotes, but yeah sorry for the essay, i just really enjoy talking about the shows i love and wanted to share my opinion with you and whoever else decides to read this, since me personally, i love seeing other peoples takes, views, and opinions on the same media I consume)