Stuck on Google Logo [Rooted] [No OS Installed]

I rooted my phone 4 weeks ago, had TWRP installed, tried to tweak my phone with "Root Booster" app, but after few days it started showing issues related to bootloop, I'm going to install latest factory image of my device through OTG,Please suggest and help. Also, i didnt took backup of my rom, when using TWRP, it shows NO OS INSTALLED.

My Device: Android 6.0.1
N5 D821 32GB

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