I have Lenovo L14 Gen1 with i5 10210u.
After digging I found out that It's not because of Balanced and Performance Mode but Actually CPU Governor,
If CPU GOVERNOR is set to powersave them Fan will work but of it is set to performance, then fan will not work,
Setting CPU GOVERNOR at powersave or sticking to Balanced Mode is Okay but I will leave performance which I get from switching to Performance Profile