I give up on diplomacy for now, and shelf the game untill at least that part works, if just a little.
I worked years on improving relations with a single nation but more then being able to give tribute i didnt come. At some point however the nation i had given tribute to offered a alliance. From there i arranged a marriage, but a trade agreement whas still neglected after 6 diplomats, wile having a max standing with them, a alliance + a marriage, and still they asked me to improve relations first
So there i whas with a shitload on merchants waiting idle in my country because they werent able to do a single thing.
And yes every 5 or 10 minutes a foreign diplomat approaches me with a offer i can't accept because they want me to improve relations first before i accept THEIR offer.