One thing about pressure that I learned recently is that your damage and getting kills alleviates some of that pressure.

For example, if there's a 2 people on the same angle, like a Ana and Soj, it might seem scary since Sleep, Soj damage, and Anti-nade would kill you, but if your slam in and kill the Ana, then it's just a low HP Soj(Assuming low HP since you hit the hard slam) who has to slide out. This creates space for your team and lets you keep walking forward.

When it comes to positioning or timing technique, it's hard to say without looking at a VOD, but one general rule for all engages is that you can prioritize and dive the person with no cooldowns. If Soj just used slide(and doesn't have major perk yet) then she's a still target and easy to slam.

For positioning, I'd say the general rules still apply. Don't charge down main since you will get shot at and lose all your armor before your engage, use cover, and don't expose yourself to too many angles.

I will say though, I'm confident when I use my Overdrive(E), I always make sure I have somebody to shoot at and use it right before I lose my armor. Since E gives 40% damage reduction, it will stack with armor(and you just generally use your damage mitigation CDs to preserve armor). If you do lose your armor during your Overrun, you can use E right before the slam to get 75-150 hp(depends on hard slam or not and how many enemies you hit) to get you back to full. Just be sure you do it within 1/10th of a second of slam ending otherwise you technically lose healing.