fair play

Sometimes, I am winning, and lichess warns that the opponent has abandoned the game and starts a countdown. When I have to choose I press the draw button, because I can't know if the opponent maybe just has a bad connection. Is that right or should I hit the victory pin?

Hit the victory pin. If you loose connection your opponent will do this.
If you are loosing or have a dread draw that you really can't win i would consider claimimg only a draw. To be honest, this has never happen to me.... It was mostly winning for me when this happened, sometimes positions still full of life.

Nah, it's far more likely that your opponent just wanted to inconvenience you than their wifi went off

Hit The Victory... You Can Not Know Ur Opponent is good or bad.
If He/She Is Ur Friend, U Can Make Draw Or Wait her/him

Affamati di elo clicchiamo "reclama la vittoria"
Dubito che qualcuno prema patta ..... se lo fa è un signore.
😀

Hungry for elo we click "claim victory"
I doubt that anyone presses a flap ..... if they do it is a gentleman.
😀

Some people just leave the game instead of resigning in a lost position so feel free to claim victory in these cases. I believe this countdown is a lot shorter if your opponent is a bad position, so you can use that as an indication of the evaluation of the position. You can also check your opponents profile page to see their "Game completion rate" to see whether they abandon games often. I'd say anything below 85% is suspect. Pressing the draw button every time would reward this inconsiderate behaviour.

If you believe your opponent disconnected in the middle of an equal game, fair thing would be to give them a draw. Or if you are in a terrible position and your opponent leaves the game, the likely scenario is that they had some business to attend to or just lost the connection, you can choose to resign in this situations if you feel generous.

@EdinburghCollective Yes, game completion rate is very important,But ı am resigning games when my opp. have checkmate in a few moves. And resigning is decreasing game completion rate,isnt it?
So my completion rate is %73 XD

https://adjva4.dpdns.org/@/Ginko58,
cavolo, è quello che ho fatto finora. Allora fino adesso sono stato un "signore" = traduci "coglione". E io che pensavo di fare bene.
Questo è un esempio

trad.:
man, that's what I've done so far. so until now I have been a "gentleman" = translate "jerk". And I thought I was doing well.
This is one example

It's generally sore losers who leave a game without resigning, but I think it's quite easy to spot the exceptions. Here's one that happened to me recently: