The main thing in a Portrait is not the subject, not the lens or the camera you are using. The most important thing is the mood. If you capture the correct mood then all other falls in place. So shoot many , shoot up close and shoot in every possible angle. Unless you are confident you can get the right shot in one click.
People use 50mm, 35mm, 135mm, 90mm and many other lenses for Portraits. All are good but each focal length requires you to be positioned at a particular distance for proper framing. While 25mm and 28mm require a much closer distance to the subject (unless you want perspective) , 50mm and 85mm allows you some distance.
Sony 85mm 1.8 is my favourite lens for normal portrait photography. By normal I mean shots where there is less scope of experiment and which are head or bust shots. Not only studio or still shots I have even used this lens for candid photography. Of course the open aperture requires careful focussing. But the Sony A7iii has ample scope of fine tune focussing given the AF-C (continuous AF) and Eye AF mode.
The main advantage of shooting wide open specially in low or moderate light condition is the gorgeous bouquet which adds a special depth to the field. With 50 mm framing is a bit easier but 85 mm helps when you can place yourself at a distance. Framing is tight and the lens renders amazing colours. And if you are a black and white shooter the A7ii gives you an option of shooting both in the Raw and JPEG. You can pre select the B&W styling for Jpeg’s while Raw files will be in full colour for post edits. I shoot in both jpeg and raw.
I do use Lightroom at times but Photoshop is more than enough for me. And yes, do remember to save action’s in photoshop for anything and everything which you do more than 3 times.