Looking back at my earlier post, I do want to go into a bit more detail! At least for my preferences, I prefer not to do any kind of combat ICly unless it’s organized or in an event.
I really don’t like unmodified /roll 20. At all. It ignores anything your character may be good or bad at and is purely luck. Guuah is a great shot. He’s been blastin’ things for a good while. It’s real awkward when he rolls a 1 and ends up shooting his foot or something.
Like I said, it’s the easiest to just jump in and do? It’s just real frustrating to see your character flounder like a fish out of water when they shouldn’t, unless you want to make several RP posts about your equipment malfunctioning.
Proper D&D systems work a lot better, purely because you have failsafes against bad luck. Modifiers to make up for low rolls, abilities that can succeed regardless, themed to your character. Still have the ability to make your actions seem cool and impactful! It’s a lot better. You won’t ever find this doing public RP, but if you find a guild or something that does something like this? Do recommend.
Freeform emotes is my preferred option, but I must stress: Never do this with some stranger. It just doesn’t work. It requires an understanding from all parties involved how their characters work, their strengths and weaknesses, and no systems tying them to it. Without that, you will have people miss or flat out ignore some things your character should do, and it becomes a competition of ‘how can I godmod this person more than they did so to me’.
I had PvP be a factor exactly once, barring my time in RP-PvP servers back in the day. I have an alt who was a Darkfuse bruiser. She’s not a nice character. She made fun of an orc’s belt that had a skull on it, and he wanted to fight her in game.
I do have a habit of playing PvE and PvP, and I have equipment sets ready for this purpose. 
It can work, as long as both parties understand that it’s going to be based on gameplay and skill, and less on words and systems. And that both parties are ready to take defeat gracefully so the story can continue or end without anyone feeling sassy or upset over it.
Just, yeah! Hyper important you hash it out with your other party(parties) beforehand, and see what everyone is comfortable with. Think the end goal is for everyone to have a good time, and have their character do neat stuff!