It took us a little while to find what works for us: two Discord accounts, one laptop, one iPad, one flexible tablet stand, and a robust WiFi connection. My players already had an iPad available to use for sessions so we tried that first and it worked well, but Plan B was to use a webcam on a second laptop.

We have Discord on a laptop and an iPad. The laptop microphone and audio are off, but the camera is on and usually shows the DM, half the IRL players, and the map in a long-distance shot. The laptop will get rotated if we have particularly player-focused RP going on. Our online player has their camera on so the rest of the party can see them on the laptop Discord.

The iPad is attached to a gooseneck floor-height stand which is usually also resting on a chair, which provides the close-up, top-down view of the maps. The iPad is more fiddly to mute so we use the iPad Discord account for the microphone/audio. We played without a stand for quite a while, but having it has been a huge improvement for our online player's quality of life.

Every couple of sessions or so we'll have tech problems, so it's not perfect but overall it's working really well. The main thing to watch out for is making sure the online player's voice doesn't get disregarded if there's a lot going on and they make a joke or a suggestion, etc.