I struggle so much with all the ways to say apple. This sentence is hard became "the horse" ends in "en" because it's an "en" noun and it's "the horse." got it. But then äpplen ends in "en" but is a plural instead of "the" because it's an "ett" noun (I assume) God if I ever reach a point if fluency where I talk instead of write it'll take me 10 mins to put together a short sentence then another 5 to figure out /remember how to pronounce it!
You may want to read about declensions in Swedish, for instance here, under "Nouns": https://www.lysator.liu.se/language/Languages/Swedish/Grammar.html