Is the heart (♡) also a traditionally Chinese symbol for love and compation, as we know it today - or is there any equivalent old symbolics in Chinese calligraphy?

Yes, the world love in chinese (愛) has the heart word (心) in the middle and the word heart (心）derived from ancient chinese pictograph that shape like a heart ♡.

Love （愛) is believed to emanate from heart from which a person admire and love another. The original word for love is 㤅, a phono-semantic compound (形聲, OC *qɯːds): phonetic 旡 (OC *kɯds) + semantic 心 (“heart”).

later 旡corrupted into 爫冖 ,with 心remain and additional 夊added at bottom to depict human, hence formed the traditional chinese word 愛.

https://youtu.be/BEiFlfUfkGI

The traditional Chinese word later evolved to 爱. Instead heart 心 it replace with the word friendship（友).

Chinese words semantic always depicting reality and the truth may be love:

1. no longer emanate from heart;
2. transcend the boundary of human.

Or

1. Maybe we discovered love is actually a result of hormone chemistry, nothing to do with heart.An

2. d such chemistry present in all living things for continuation of gene.  

3. Perhaps, friendship is more important to keep relationship going now.

Friendship indeed surpass love for survival in today context. In the dog eat dog world era now, it is how you can exchange benefit with another (friend) to form a mutual benefit relationship(friendship), with or without genuine affection or emotion(heartless💔).

Unconditional love seems to be a thing of past now!