How to convert a lamp with fluorescent lamps to LED

Good afternoon! At home, fixtures with fluorescent lamps are installed. Apparently, they served their term. You press the switch - the lamp burns for 60-10 seconds and goes out. The lamps are brand new, barely barely found in Moscow at 24w. It turned out to be unrealistic to find ballast for this lamp in Moscow (helvar el3 4x24s). I’m thinking of replacing the interior of the fixtures with led. As I understand it, it is necessary to select lamps of similar dimensions, replace the starters and connect directly to the network. How real is it? I do not want to change all the lights in the house, because I really like them, but I did not find the same ones, but led. I need your advice on how to make it more profitable and more expedient. And if you rebuild it, then advice or detailed instructions - how. Thanks in advance!