1) I was reading in an ahadith collection and I read that mast*rbation is like fornication and that fornication is an for which Hellfire is deserved.

2) But I remember a hadith which says thay even though mast*rbation is like fornication there's no actual punishment for it. If there isn't a punishment for it, does that mean one wouldn't go to Jahannom for it?

3) But is it permissible to mast*rbate with one's wife? And I don't mean mast*bating eachother, I mean like if a husband and wife are far from eachother and go on a phone/video call and mast*rbate with eachother. I remember a hadith that said if a man rubs himself again a woman with his clothes on until he ejaculates it's a sin.

4) I know that the Qur'an says the approach one's wife however you please. Wouldn't doing this with one's spouse count as that?
I also find the contents of the hadith about rubbing against your wife with your clothed on suspicious and to still be contradictory with the verse. As the man is still using the woman.
And in my case, I'm still using my wife and I'm experiencing her the only way available to me.

5) Are there any du’as for when one wishes to travel but can't? And any du’as for when one is far from one's spouse and wishes to be with them?

1) When we examine all the hadiths on masturbation, it’s clear that it is a sin. Yes it doesn’t have a kaffara or an official punishment (hadd) but it’s sinful.

2) No that’s not what it means
It means there is no set worldly punishment for it. But it’s still a sin

As for Jahannam, if one deliberately sins and takes God lightly and doesn’t repent then the person may end up in Jahannam. Otherwise Allah is merciful

3) And masturbating when calling a spouse is not permissible. It would still be sinful. One must be patient and try his best not to stay away from his wife. Make this a priority in your life.

4) Yes one can approach his wife in any manner. But masturbation is not approaching one’s wife. It’s approaching oneself.

Also, you are using your wife only by seeing/talking to her—not physically. Technically, physically you are not using your wife. Hence it’s not permissible.

5) I am not aware or any specific Du’as for that, but any general Du’a for the fulfillment of needs would be good.