Instead of a blanket approach, use an app like ActionDash / Digital Wellbeing for a week ( turn off their reminders to keep the phone usage behaviour unconsciously the same for a week more )
Analyse your phone usage patterns (early morning post waking up, late night after going to bed) and apps are consuming most of your time. Turn off notification permission for all the redundant apps.
Particularly for Whatsapp, mute as many groups as possible. Because it is now a primary communication app, turning off Whatsapp notification might not be a good idea because you might end up checking it way more often.
Avoid taking phones to bed - it is a place for resting your body. Do not make it a place where you are excited to see Instagram and all the social media.
Hope this helps.
The short answer is to track your phone usage for a few days, then set time limits and install blocking apps that limit your screen time. Mute all notifications. Here you're trying to control your external behaviour by imposing restrictions that prevent you from accessing your phone.
The more effective and longer-term approach is to make an internal change. Understand what habits drive your behaviour. What is it that prompts you to pick up the phone and open Instagram or WhatsApp? What is the trigger that prompts the specific behaviour? Identify and replace current undesirable habits with more desirable ones. Reinforce that behaviour.
This type of internal change takes a while but is more sustainable.
There are various applications on play store that will help you track your device usage, application usage, screen timings etc. And will help you to limit your screen timings