A first, bad, ascent option is adding air to your BC, like an elevator, to somehow ride that up while venting. Edit: Risky as your are adding BC air that will just have to be dumped, making overcompensation, and runaways, more likely.
Gently finning up is a second option, and far preferable to the first, also with BC venting when needed. Its strong preference over option one is a likely cause for any Padi emphasis, as option one is a bad idea.
A third option is to shift slightly the normal cycle of your breathing. Your breath normally cycles you between slightly buoyant and slightly negative, but on average neutral. By shifting it to be slightly buoyant more often, you drift up gently, which is the rate you want. Then periodically vent BC air as needed so that you would return to neutral buoyancy if you resumed an even, balanced, breath cycle. It is important to emphasize that you are *not* holding your breath! You just spend more of it with fuller lungs and less of it with emptier lungs. You remain horizontal when you initiate ascent and for all of it except the last few feet below the surface. All very different from a buoyant emergency ascent.
Normal tidal volume, how much we inhale and exhale for a relaxed breath, is +-0.5 pints so 1 pound range total for men and women. Men have a 7 pint inspiratory reserve above that and a 2 pint expiratory reserve below that. Women have +4.5 pints and -3 pints. So there is a large buoyancy range to your lungs while staying far away from full inflation. Just shifting the timing of your inhale/exhale cycle, and not even the range, will make you more positive and drift you up. That is all you need.
Here is a rather nice GUE video on buoyancy. It describes using lungs as part of your buoyancy control, though not so much the details of ascent. GUE is one of the premier technical diving organizations.
Horizontal trim at SS helps increase vertical drag and make depth control easier at a depth where it is the hardest. It also makes horizontal movement easier by reducing horizontal drag and making that where your fins point. We want slow vertical movement, but might want to move to or away from our buddy for various reasons.
OP, a weight belt might help move lead lower, depending on your setup.