They both refer to a concept of "compromise"
According to this, it 妥協 has some negative meaning in the sense that one is left with no choice but to compromise, but 折衷 is more like taking the good aspect of each thing (e.g., proposal).
I would like to know if I have the same understanding as a typical Japanese speaker.
Your understanding of 妥協 seems fine.
折衷 is an uncommon word that means "blend", "fusion", "mix", etc. It's rarely used outside a few fixed phrases such as 和洋折衷 ("mixed-Japanese-Western style") and 折衷案. 折衷案 literally means "blended proposal", but it can be usually translated as "happy medium" or "compromised suggestion".
