If you look at Fabrizio Romano tweet, it seems that a true verbal agreement has been reached, which means it could be that Ramos has agreed on the amount of salary he will receive. However, on the other hand, I don't know for sure why Ramos is reluctant to join the Saudi Pro Legue. In my estimation, Al Ittihad does not want to give the amount of salary that Ramos wants, in the sense that he is not unable to.
Or another possibility is that Ramos will go to the SPL in the following season, after defending Sevilla for one season first. It is difficult to predict because Ramos has free transfer status, he can go to any club without transfer restrictions.
I saw a new tweet a few hours ago still sourced from Fabrizio Romano stating that Ramos "Here We Go" to Sevilla which means we know what it means when Fabrizio has said that then most likely it is agreed and Ramos returns to La Liga and reunites with the first club that raised his name before being taken to Madrid.
Ramos seems to want to end his career with the club he started in professional competition and indeed this is possible if you look at Ramos' age then it is likely that after Sevilla he will leave and leave football as a professional player.