替代textContent修改Facebook聊天框span文本的方案咨询

我在Facebook网页的JS控制台尝试发送消息，能够成功发送，但无法使用textContent修改聊天框内的span文本。在聊天框输入内容时会生成一个span元素，我想要修改该span的文本内容，但使用textContent修改后，控制台输出仍为原元素，说明span未被更新。

element=document.querySelector("#mount_0_0_wY > div > div:nth-child(1) > div > div.x9f619.x1n2onr6.x1ja2u2z > div > div > div.x5yr21d.x1n2onr6.xh8yej3.x1t2pt76.x1plvlek.xryxfnj > div > div > div.x78zum5.xdt5ytf.x10cihs4.x1t2pt76.x1n2onr6.x1ja2u2z > div.x9f619.x2lah0s.x1nhvcw1.x1qjc9v5.xozqiw3.x1q0g3np.x78zum5.x1iyjqo2.x1t2pt76.x1n2onr6.x1ja2u2z > div.x9f619.x1n2onr6.x1ja2u2z.xdt5ytf.x193iq5w.xeuugli.x1r8uery.x1iyjqo2.xs83m0k.x78zum5.x1t2pt76 > div > div > div > div > div > div > div.x1uvtmcs.x4k7w5x.x1h91t0o.x1beo9mf.xaigb6o.x12ejxvf.x3igimt.xarpa2k.xedcshv.x1lytzrv.x1t2pt76.x7ja8zs.x1n2onr6.x1qrby5j.x1jfb8zj > div > div > div:nth-child(2) > div > div > div.x78zum5.x1iyjqo2.x6q2ic0 > div.xmjcpbm.x107yiy2.xv8uw2v.x1tfwpuw.x2g32xy.x9f619.x1iyjqo2.xeuugli > div > div > div > p > span");
console.log(element);
console.log(element.textContent);
element.textContent="Enes";
console.log(element);
//document.querySelector("#mount_0_0_wY > div > div:nth-child(1) > div > div.x9f619.x1n2onr6.x1ja2u2z > div > div > div.x5yr21d.x1n2onr6.xh8yej3.x1t2pt76.x1plvlek.xryxfnj > div > div > div.x78zum5.xdt5ytf.x10cihs4.x1t2pt76.x1n2onr6.x1ja2u2z > div.x9f619.x2lah0s.x1nhvcw1.x1qjc9v5.xozqiw3.x1q0g3np.x78zum5.x1iyjqo2.x1t2pt76.x1n2onr6.x1ja2u2z > div.x9f619.x1n2onr6.x1ja2u2z.xdt5ytf.x193iq5w.xeuugli.x1r8uery.x1iyjqo2.xs83m0k.x78zum5.x1t2pt76 > div > div > div > div > div > div > div.x1uvtmcs.x4k7w5x.x1h91t0o.x1beo9mf.xaigb6o.x12ejxvf.x3igimt.xarpa2k.xedcshv.x1lytzrv.x1t2pt76.x7ja8zs.x1n2onr6.x1qrby5j.x1jfb8zj > div > div > div:nth-child(2) > div > span.x4k7w5x.x1h91t0o.x1h9r5lt.xv2umb2.x1beo9mf.xaigb6o.x12ejxvf.x3igimt.xarpa2k.xedcshv.x1lytzrv.x1t2pt76.x7ja8zs.x1qrby5j.x3nfvp2 > div").click();

内容的提问来源于stack exchange，提问作者saitamatechno