That newest leaf is a beauty!! These philos are similar because they are cultivars of P. erubescens.
This plant isn't large enough to propagate, IMO, with just 2-3 nodes below the growth tip, on the part in the forefront. The other section's stem isn't visible. But that's just a matter of personal visual preference, and you should do what you want no matter what I would prefer on my own plant.
You could allow stems to lean on the soil, which will encourage the aerial root nubs to form actual roots, and is how it would grow along the forest floor in nature until finding a suitable trunk to climb. When a node takes root, it usually also sends out a new growth tip. Since there are 2 stems, there's no reason you should fear losing your plant by trimming one of them. As long as the stump you leave has a node above soil, it should grow a new tip.
As these plants are epiphytes, they don't need much soil, or for the soil to be moist constantly. The loss of the older leaves so close to the growth tip (a sign of root impairment) concerns me that your plant might like to dry for longer periods between waterings.
A humidity tent shouldn't be necessary in summer, outside. Restricted air flow is the milieu of fungus and other pathogens.
The parts circled in purple are the nodes, where the aerial root nubs are (circled in red, if my eyesight is interpreting the pic correctly.)
Here's another piece of the plain burgundy Philo from above, a leafless section of stem stuck in this pot about a year ago.
Here's the plant on the left from above pic, the 2 stems are coming from the same section of stem although one starts under the soil surface. After about a year, it's going to discard one of its' first leaves (and has sand splashed all over it from all of the rain lately.) You can see the aerial roots searching for something to attach to, not necessarily soil. (They will adhere to metal, wood, walls... in addition to the natural plan of a tree trunk)
This plain green one may be one of the ancestors of the new cultivars. Rescued from "the ICU" at a garden center a few months ago, only had a couple leaves per stem. You can see the similar stems and aerial roots.
When I brought it home I repotted it and the stem was too long to fit how I wanted it in the pot. I removed this piece and stuck it in the soil. Looks like it's about ready to make a new tip.
Heart-leaf Philo has a great example of what happens when a Philo's tip is removed. A new tip will form somewhere, sometimes multiples.
Unless the air gets too dry, aerial Philo roots will grow indefinitely until they either reach soil or something to which to attach and provide stability.
HTH give you an idea of what your plant can do!
