Mobile In range of 12K-18K

I am also in the market. Not purchasing any Xiaomi phone as they get to buggy after 1 year.

I have shortlisted between Samsung F41 and M21.

Any other options?

But my 3s prime worked well for 2 years but nowdays i don’t feel it’s better quality.

My 2 years old asus zenfone max Pro m1 is still working butter smooth having 5000mah battery.

During sale days, you can buy realme 7 or narzo 20pro for around 12-13k or go for motorola g9 power. on the higher side you can go for poco x2 or motorola g 5g.
else i am expecting mi 10i and realme x3 to come down in the sale.
over all i am happy with realme 7 that i have and narzo 20pro very similar with faster charging. and motorola would have really good hardware and software. i have poco m2 at my place but it lags sometimes.

Even Poco X3 might be a good option

Buy secondhand flagship.. Eg. Realme x2 pro or oneplus 7t

Smart buy will only give 1% on Fk

Motorola one fusion+ if u r ok with 4g . Buy with card offers

Is there any 6-6.4", 6000mah , sd smartphone?

To increase battery turn off 4G data.. On some phones this uses a huge amount of battery since the phone uses normal 600mah to connect to tower but to get better connection this jumps to 3000mah.. Some have good implementaion of 4G connections and some dont. Just as an example on my old nexus phone it has a standby lasting more than 1.5 week with only 2G and over 5 days with 4G data turned off.. The battery only lasts like 6-8 hours with 4G data turned on..

One of the best uses of the jiofi wifi is for this.. especially when travelling.. wifi only uses like 300mah of power.. also far easier to charge the jiofi from a powerbank than the phone..

and the best part is it dont fry your brain cells when the power levels spike to 3000+mah..