The side

I like having it on top for being able to set my phone up against something still, but if it’s in my pocket I want the top of my phone down so I take it out it’s right, which means the bottom Jack works better. So ideally I’d want both

Yes

All phones I've had, had the jack on the bottom where it's in the way of me holding the phone or placing the phone on something. I always wondered why it's not just at the top.

BTW just got a new phone (Oneplus) and I'm glad to have found one that has a jack at all

What privacy respecting phone are you using that also has a headphone jack? If it has an sd card slot too I'll think I've gone back a decade

None, because I use wireless on the phone. Tablet/laptop is used when I need fidelity.

Bottom. All phones I've ever had have the headphone jack at the bottom, right next to the charging port. So, why would I want it anywhere else than where I'm used to it being?

On the back so it doesn’t get in the way.

But seriously, neither. If I’m listening on my phone I’ll be out and about, and don’t want wires in the way. Bluetooth all the way.

At home, via a decent DAC hooked up to a PC.

Top right.
It's best place when holding it in landscape mode.

bottom, so I can charge it and have headphones plugged in at the same time while it's in my pocket.

I had the last generation iPod nano, and none of the clip-on cases I could find would put it upside down like the way I preferred my phone so I cut it with an exacto knife to reverse it

I do not care about having a headphone jack, but it would be nice to have the charging port on top; it's more out of the way for me.

Anywhere but the bottom half of the phone. I hate that the charging port is on the bottom. It’s in the way when I need to use my phone while charging.

The side of the phone.

Get out your pitchforks because I prefer headphone jacks to be a thing in the past

I haven't used either so no clue. No headphone jack on the s21

Edit: why was I downvoted?

I don't think I've seen one at the top..

I'd say bottom because I'd rather not have the cord coming towards me, rather than away, when I'm using the phone. Also it seems more ergonomic for me to put my phone in my pocket with the top pointed down rather than up.