Sites open after 2-3 seconds?

Routing issues I guess. Same for me in Patna.

Could happen with small packet loss. Try pinging a site for an hour and see what percentage of packets are dropped.

Or as DaRkLoRdB2 said, routing issues. Post traceroutes to slow loading sites here.

Routing on airtel is pretty weird, at least for me

I have 2 xstream fiber connection, one is using Nokia nokia G-2425G-A, another one is using nokia g140w-f
Nokia G-2425G-A one seems to woks fine except sometimes it takes 2-3 seconds to load google search results

The real problem is the g140w-f connection I have, international speed is lower than my G2425G-A connection, surprisingly routing is different if I am directly connected to wifi of ONT, through Ethernet or through a router connected to Ethernet, Wi-Fi of ONT > Ethernet > Wi-Fi connected to Ethernet
Routing of all 3 combinations is different, tried multiple combinations of routers and clients but same results

The only reason I have not disconnected my nokia g140w-f connection is because it's in bridge mode connected to a switch, apparently there is no limit on number of pppoe and IP addresses I can connect using it, currently it's running 2 static IP address and 2 pppoe connection.
Every device I connect to my unmanaged switch can have its own dedicated speed and IP address using pppoe

Another surprising thing is that if multiple pppoe connection is connected to multiple wifi routers, the combined wifi speed is my plan speed but if connect using Ethernet, each has its dedicated bandwidth.

TLDR - it's a pretty complex routing issue which is pretty much impossible to explain to airtel enginners.

Cloudflare's warp+ does not solve the issue, the only thing that solves it is a proper wireguard VPN

@Rehan Kumar why two connection were required ?

which router of airtel you got Nokia or huwawei

and how is the airtel service , do this lovely guy cut their cable

Nope coz all is underground like landline copper before.
I hope airtel fiber is available in ur area. You can try jio either.

I also feel fiber is sometimes slower than 4G. I also see some packet loss some times, like 10 in 7000 packets. So I'm not even sure what to say to Airtel people, plus you'd have to probably deal with all the annoying "close all apps, install antivirus". Sometimes YT defaults to 720p60fps to, and I have to switch it back

Airtel installation team has to complete targets on no of installation every month so the work is done in hurry. Splicing is not done properly.
From my junction box(-19db) signal dropped to -27.2 with just 10met of fiber. Assistant was doing splicing that too on 4th or 5th try.
I am hoping fault team wont be having target.
Though i am not facing any problem for now but would definitely get this redone.

What is the relevant number? There are two numbers -17dbm and -27dbm and other are 2 and 0 in my stats page

Rx dbm is relevant.

Then its at -17.55dbm for me which seems ok

yes -17 is very good