Question Urgent help needed with misbehaving UPS ?

[Kirito-kun]

My specs
Motherboard: H61
CPU: i5-3570
GPU: RTX 2060
RAM: 2 x 4GB
PSU: 550W Bronze+ CM
2 x SSD, 2 x HDD
RGB Keyboard and Mouse
Bluetooth and WIFI Adapter
Case Fans: 3 x ARGB and 1 x non-RGB
Monitor: Acer 22 inch IPS

I have a inverter at my place but due to frequent power cuts in my area, I bought an
ENTER UPS E-U740 LINE UPS (Output Power Wattage: 360 W) from a local shop to protect my GPU for that 1 minute when the electricity cuts off and switches to Inverter, it provides good backup during normal usage (when GPU is not in use), but whenever I am playing games COD series, GTA V, the moment the electricity goes off my pc crashes and then in next second the inverter kicks in, it restarts.

I thought there was something wrong with my UPS so I took my PC and UPS to the shop, but there it managed to play GTA V, Genshin Impact and COD:MW Remastered for total 4-5 minutes before discharging. I brought it back home, separated Monitor connection directly to board and tested same thing (switched off power connection during Genshin and it survived), I thought it solved the problem but again just 30 mins back , my friend was playing COD:MW and electricity goes off and again PC goes off. This is so much frustrating!!! Please need urgent help!!!

Another point to Note: When I am cutting off the electricity first and starting PC on UPS directly, I am able to run few games (Genshin , COD:MW, GTA V) for few minutes, but whenever I am playing on electricity through UPS, the moment electricity goes off the PC shuts down, the UPS is not providing even a one second backup.

 

[Ralston18]

A UPS is intended to provide the required amount of power to keep the supported system running long enough for the end user to initiate a proper shutdown.

Not to continue playing which may be moot because power outages usually cause internet connectivity to be lost.

Also the U740 does not appear capable of providing the power (and thus time) needed for a normal shutdown.

Update your post to include full system hardware specs and OS information.

What other devices are also connected to the UPS? l would expect the PC and at least one monitor.

Anything else?