Random flickering in Safari after iOS 18 update

Recently I downloaded Safari 18.0 along with Sonoma 14.7 update.

However after the update, Safari is showing random flickering that looks like auto page refresh (the search bar typing pauses and extension closes whenever the flicker happens). For example, Adguard icon next to the search/address bar, we can right click to access setting options. In my case, the drop down menu disappears whenever the browser flickers. This happens to other extension in Safari and not on chrome or Firefox.

I’ve tried restarting the browser and the laptop, but to no avail.

Does anyone have a solution? Thanks in advance!

[Re-Titled by Moderator]