Developed first tasker project! great thanks to @Ratchet_Guy.

Here are the profiles.

Profile: dailytimelimiter (12) Event: Display On Enter: screenon (4) A1: Variable Set [ Name:%Screenon_since To:%TIMES Do Maths:Off Append:Off ] A2: If [ %Limiter_date neq %DATE ] A3: Variable Set [ Name:%Stime_left To:3600 Do Maths:Off Append:Off ] A4: Variable Set [ Name:%Stime_warn To:0 Do Maths:Off Append:Off ] A5: Variable Set [ Name:%Limiter_date To:%DATE Do Maths:Off Append:Off ] A6: End If A7: Wait [ MS:0 Seconds:%Stime_left - 300 Minutes:0 Hours:0 Days:0 ] If [ %Stime_left > 300 ] A8: If [ %Stime_warn = 0 ] A9: Popup [ Title:Warning Text:5 minutes screen time left Background Image: Layout:warning Timeout (Seconds):3 Show Over Keyguard:On ] A10: Variable Add [ Name:%Stime_warn Value:1 Wrap Around:0 ] A11: Wait [ MS:0 Seconds:0 Minutes:5 Hours:0 Days:0 ] A12: Else A13: If [ %Stime_left > 0 ] A14: Wait [ MS:0 Seconds:%Stime_left Minutes:0 Hours:0 Days:0 ] A15: Else A16: Variable Add [ Name:%Screenoff_since Value:600 Wrap Around:0 ] A17: Wait [ MS:0 Seconds:0 Minutes:2 Hours:0 Days:0 ] If [ %Screenoff_since < %Screenon_since ] A18: End If A19: End If A20: Lock [ Title:Timeover Code:123456 Allow Cancel:Off Remember Till Off:Off Full Screen:Off Background Image: Layout:Lock ] A21: Show Scene [ Name:addminute Display As:Activity, Full Window Horizontal Position:100 Vertical Position:100 Animation:System Show Exit Button:On Continue Task Immediately:On ]

Profile: Displayoff (8) Event: Display Off Enter: screenoff (11) Abort Existing Task A1: Stop [ With Error:Off Task:screenon ] A2: Variable Set [ Name:%Screenoff_since To:%TIMES Do Maths:Off Append:Off ] A3: Variable Add [ Name:%Stime_left Value:%Screenon_since Wrap Around:0 ] A4: Variable Subtract [ Name:%Stime_left Value:%Screenoff_since Wrap Around:0 ]

Profile: reboot (2) Event: Device Shutdown Enter: screenoff (11) Abort Existing Task A1: Stop [ With Error:Off Task:screenon ] A2: Variable Set [ Name:%Screenoff_since To:%TIMES Do Maths:Off Append:Off ] A3: Variable Add [ Name:%Stime_left Value:%Screenon_since Wrap Around:0 ] A4: Variable Subtract [ Name:%Stime_left Value:%Screenoff_since Wrap Around:0 ]