https://appleinsider.com/inside/iphone/tips/how-to-automate-iphone-reboots-to-improve-performance-security
Please read more at the above link
A smooth-running iPhone doesn’t happen by accident — it requires some care, like regular reboots to clear temporary files and refresh system processes.
One easy yet often overlooked way to boost iPhone performance is through regular reboots. Automating this process saves time and ensures your device stays efficient and responsive.
For example, apps frequently store temporary data, and a restart clears out this clutter, allowing your iPhone to run more efficiently.
Another advantage of frequent reboots is security. Restarting your device refreshes system processes, which can reduce the risk of vulnerabilities being exploited.