Being in a big team is like that, if the team continues to experience negative results then the pressure will be even greater. In fact, the fault does not lie entirely on Xavi's shoulders with Barcelona's current downturn. At Barcelona, goalkeepers have always played an important role in defence, with ter Stegen taking the role of sweeper. However, Pena failed to play this role and continued to make mistakes which resulted in Barcelona often conceding goals.
Apart from that the problem with Xavi is that his tactics and ideas are not yet fully developed. He managed to win La Liga which makes me think he has the potential to be a great manager, but he needs time to develop but barcelona fans don't believe in the process. In my opinion, Xavi's departure is the best decision for all parties involved, he can gain experience at a club where there is less pressure because there is a good coach there.
If there is a coach who has better potential for Barcelona then just show him who it is because even a new coach will definitely be defeated if the fans want the club's performance to match their expectations while the management does not support financially in adding to the squad that is needed then Barcelona will not achieve the balance, of coaches either needs support to achieve the expected success. If at Barcelona he feels pressured and Barcelona does not try to keep Xavi then it is better to leave and choose a club that can support him financially and does not have heavy pressure.