Hey I've got some extensive experience and tried spoofing location and many other tricks but once a group gets reported for porn on telegram it goes down.
However, using the search function in telegram you can usually find unreported groups or album link (packs) groups. You need to use "caliente" "jovencita" "packs por mega" or other tricks to find these link groups.
They are as you've probably guessed, from latin american sources. Be careful to avoid UA content.
There are also some indian groups if that's your thing but again these groups are constantly being reported (ped content) and coming back online.
"backup" (you can search for this) channels exist but yeah the heyday of telegram amateur porn is pretty much gone.