whats the purpose of this? i understand that it will reset the lvls of all my characters but what then?

does it just exist to make the characters brutally OverPowered to solo everything

is there any way i can have fun with this?
such as a NG+ with uncapped lvls and hard mode
or NOT carrying over character levels, therefore making every character a true lvl 1 but with no stat cap

has anyone played around with this and found more to get out of this other than the brutal character result?

Its purpose is right what you said: resetting the character from lvl 99 to lvl 1 while retaining all stats, skills and rank.
However, I wouldn't say it results in "brutally overpowered" characters, just allows them to grow further after reaching level cap.

Also, if you don't carry over the character levels, you will lose both levels and rank, meaning all stat caps will be reset.

sorta having trouble understanding that last part, but are you saying its possible to transmigrate the characters from 99 - 1 & then start a new game as true lvl 1's (not carrying over stats) but having no stat cap?

if possible that would be really fun for a new game as id be able to use characters like suina for a new game whos stats blew chunks due to the stat cap

ahh shame, i was really hoping it would work out the other way.
thnx for the input either way

have you tried playing a few heros after transmutation because i was under the impression they become way too powerfull for a proper playthrough

The fountain is highly useful for EX dungeons and Deep Mines. Also, some characters are woefully underpowered and need a few trips through the fountain to catch up to your good characters.

Transmigrated character is useful for hard mode and they can survive alone without relying too much on item or other character.

its useful, but seems counter productive since u get it AFTER you beat the hardest dungeon(s)