The answer to your question is "yes." Yes you can lose weight and yes you can keep it off.
But you are unlikely to do it by willpower. That involves pitting your wits against the desire to eat, a contest you are unlikely to win in the long run. Been there, done that, bought the t-shirt!
Rather than beating yourself up over being overweight and treating the symptom (the overeating) you need to address WHY you overeat. There's a whole lot of stuff we could do on that, but here's something you can start right now. It might sound a bit weird :-), but it does work:
a) Write down all the thoughts you have about yourself and food. You included some in your post "I clearly lack willpower to simply eat less crap", "the lockdown was all the excuse I needed to stop even trying." Keep writing it all down, everything you think about you and food, every belief, excuse, reason, everything.
b) Look at that list and ask yourself how all the statements in a) make you feel? Write those feelings down. Looking at the statements in your post I'll posit that one feeling might be something like "frustrated". Just for an example.Then ask yourself: would someone who is feeling "frustrated" be willing to do the consistent work needed to lose weight? I would suggest not. So by beating yourself up with negative thoughts, you make yourself feel more "frustrated" which, in turn, leads you to take no action to lose weight - confirming your initial thoughts that you're no good at weight loss. It's a vicious cycle, but the really excellent news is that you can change this for good.
c) So now I want you to pick a feeling you will CHOOSE to feel about you losing weight. It has to be something you can believe. How about courage? If you feel courageous are you more likely be willing to start taking the action needed to adapt your eating habits? I would suggest yes, and certainly far more than someone who feels "frustrated" (as in the above example).
d) Finally identify what you'd need to think to make yourself feel courageous. Perhaps "I am willing to believe I've got what it takes to lose xxx kg."
Then practice. Practice the new thoughts. Actively experience the new feelings they give you. The kind of feelings that will spur you into taking the actions needed to lose weight. All the while being VERY kind to yourself. You've lost and regained weight before. So what? That doesn't mean you're stuck that way for ever. You're starting right now.
There's lots more that follows that I could suggest, but start with this for now. Let me know how you get on.