I think the home inverter/ups thread from last time is wiped from history. Could people please provide recommendations for quality inverters (batteries are separate?) that can cater to a WFH scenarios? (Load: 3 fans, 5 LED bulbs, desktop rig + multiple monitors + router, laptop, fridge, TV)

I use this one - https://www.luminousindia.com/zelio-1100.html . I have mostly the same requirements as yours but instead of a desktop, I have a laptop. For power capacity requirement, I think you can use any online calculator. Just check the power consumption of your desktop (80% of rates PSU capacity would be a good estimate) and all other items are pretty standard like lights, fans, etc.

For these kind of stuff I generally go with what local provider nearest to my home suggests. Cz they are comfortable with troubleshooting the brand they work with and you want some one who can arrive fast to troubleshoot at your home. I have SF sonic prima with Goldstar batteries. I was also narrowing down to luminous or microtek but my local provider suggested this and its almost 2 years now I have not faced any issues.

Thanks for the inputs, folks. From an online calculator my desktop + 3 monitors use 385W. This and lights + fans + router + laptop are the max continuous load I'd consider. I have a 1000VA APC UPS connected to my desktop+2-monitors+router - I forget worst case, but I recall getting some 45 minutes once on it. I suppose duration depends on battery capacity (more AH?). My flat has a MCB panel with switches for each room/area. I suppose I have to pick from here which sections go through UPS.

From an online calculator my desktop + 3 monitors use 385W

Very doubtful. What CPU GPU is your config? What's you desktop PSU?