> AFAIK there’s now way to “tell” the gender of a word in German

That's incorrect, there are rules. (These rules have a few exceptions.)

m: -en, -er, -ig, -ismus, -ist, -ling, -m, -or

f: -ät, -e, -ei, -enz, -heit, -ie, -ik, -in, -ion, -keit, -schaft, -ung, -ur

n: -chen, -lein, -ment, -nis, -tum, -um

That makes the proposed contrast weaker than you initially thought.