There's a word for "downgrade" in Spanish, why not use it?

The main change is done with the expression "grupo normal" which I changed to to "regular group". Talking about a "grupo normal" may have negative connotations. Saying if a group is normal or not is tied to a different theme that does not apply for this message. In this case, we should talk about "regular groups" or "supergroups". A group that has the default setting is a "regular group" and that's my literal translation: "grupo regular".
Also, the current selected translation says: "Esta acción es irreversible. No puedes convertir un supergrupo en un grupo normal." The expressoin "No puedes" means "you can't". The original message does not point the action towards a person (you), so there's no need to have it in the translated message.

"No se puede" means the action is impersonal and has to do with the way the app is built.

"downgrade" can be translated as "degradar" "bajar categoría "or other more appropriate words