In offline market you will get better Configuration Laptop at same price then with any online sellers. Just a month before my friend bought i3-12th Gen Lenovo (15.6 inch) just for 21.5K (Refurbished with 1 year warranty), the same laptop cost 30-32k Brand New.
i5-4th Gen will be better than i3-6th Gen in day to day work (at least for office work)
In either Gen you MUST have at least 16GB RAM without it your laptop work/uses (experience) will be very very slow.
The work you do with any Laptop is important for you (important data) than Windwos11 is better from Future update (as from Oct.2025 Windows10 will stop providing FREE security Updates and you need to Pay to Microsoft with Windows10 updates after Oct.2025)
PS: I upgrade to i3-6th Generation and really missed Work SPEED enjoyed with i5-2nd Generation.