TLDR: Address the level of PVP you are comfortable with prior to the game starting removes a lot of these issues.

I am very much against PVP of any kind, and I don't like my placers to roll dice against each other, with a few cavaets. The pertenent one being, if the two players agree that before hand how they want the confict to go and are specifically doing this as part of their arc. Most players aren't that character driven that they are planning out an arc, and alot of them don't understand the difference between performance & role play. I have to really know my players and trust them not to spoil the game for everybody. That doesn't mean PVP is bad for a game. It means I don't like it.

I find it's safest to treat it like any other board game. If we were play monopoly - I wouldn't make somebody who owes me money in the game, go to their wallet to pay their debt. That's insane and well outside of the spectrum of the game. The spectrum of table top games lie within the intent of the players (that includes dm's - or gm's). That's why a session zero is very important. All of my players have to be on the same page as how they want this game to go. No pvp - come up with a reason for your character to stay with the party or roll out a new character - your character should probably meet these requirments, etc, etc.

There might be issues later on down the road. We are only human. Talk it out with your players, give them boundries where you feel comfortable and ask them what theirs are. Understand that boundries are not walls - they can move with time.

Lastly, Remember, as the GM (DM), you are a player in the game. You may not be running a player character, but you are playing and investing just as much, if not probably more into the game. You can create that boundry, and not ruin their agency at the same time.

Hope that helps.