I had a previous incident with my bike, and the front brake got bent. Now when I try to use the front brake, it is very weak (when I ride the bike and fully depress the front brake, the bike does not stop quickly). I tried to fine-tune the disk brake caliper (I did it many times before), and it looks good and tight, but the front brake. What could be the reasons for this?
Assuming you have a cable disc brake, it could be because the cable slipped in the hold maybe.
Undo the cable and pull it tight. Check the line and make sure there's no slack. Make sure the cable housing is tightly tucked into the barrel adjuster on both sides. Then tighten it back down.
If the brake handle was bent in a perverse way, there could be a deviation in the metal that's causing distance between the pull. You'll need to replace the brake lever in that case.
Thank you for your advice. Sorry for not responding, had some issues in my personal life. After your advice and watching numerous YouTube videos, I identified that a possible problem is with brake pads, and indeed, they had some oil on them. I cleaned them with acetone (I had to soak them in it for an hour) and disks. The bike now breaks strongly and works perfectly. Thank you once more for your help!