I need to buy a compact super bright flashlight, use AA batteries
I already have the charger and 4 AA Eneloop 1900mAh rechargeable batteries.
Please advise and share your experiences
As a previous commenter said, you aren't going to get "super bright" out of any AA-powered light by most standards, at least not for more than a few seconds.
The truth is, a single 21700 light isn't really all that much bigger than a 2xAA light.
The only real advantage a AA light has is ease of finding batteries that will work in it. If you want "super bright", you need bigger batteries that are capable of sustaining high current drain.
For example:
Fenix E20 v2.0 (2xAA): 127 mm L x 21 mm D (head), 16.8 mm (body), 42 g without batteries
Fenix PD36 TAC (1x21700): 140 mm L x 26.5 mm (head), 25.4 mm (body), 92 g without battery
The E20 will put out a maximum of 350 lumens, but it will do so only for a very short period of time (about 30 min, according to Fenix), before falling back to about 200-250 lumens.
The PD36 TAC has a maximum output of 3000 lumens, but in its "Medium" mode will sustain 350 lumens for over 10 hours.