Aristois for 21w14a snapshot
I saw in some forums that it was possible to use aristois in snapshot but the procedure did not work for me and I do not know if it is true or false and if it is true I would like to know how it is done.
It is possible, however for 1.17 snapshots you need to modify some additional things.
It would help if you could join our Guild and DM me, but I could try to help here.
If it's crashing on launch, please send the crash log from /logs/latest.log, or send your output launcher contents.