In case this question still lingers on yours or other users' mind ... Pressurized PF is not PS, so to speak, as long as the whole setup is operated well, including expectations of your own tastebuds.
1) First of all, get the FRESH COFFEE. Even preground, espresso grind, bricks could work ok if reasonably fresh (if you can tolerate too much Robusta). Older or stale coffee won't yield much crema.
2) Make yourself a cup just with freshly boiled water, right in a cup, kind of a la Turka (2tbl spoons or so per 6oz). Do you like the general flavor? You'll see some crema too, the fresher the coffee, the thicker the crema. If not, get other coffee beans.
3) Next, make sure your machine gets the water HOT ENOUGH (over 90C).
I assume that your machine is able to build up enough pressure to open up the flow through your pressurized PF.
4) Now, you should time how soon you get the flow after turning on the pump with EMPTY PF, that is no coffee in the basket at all. This gives you idea how long at minimum the coffee would brew while locked up in the basket. It would only continue to brew more after the flow begins.
5) Then, the trickiest part - ask yourself what sort of EXPECTED TASTE are you chasing. It's not trivial, many of us are not familiar with "true" espresso. Not only because it's subjective, but simply due to lack of available choices out there to compare. Lots of cafes standardise to the balance for the milk-based drinks, which masks a lot of flavor details. The result is your palate simply may not be "calibrated" for the raw shots.
In case you're just developing your taste, get some help from your equpment to taste some variations!
6) Load your PF to the top of the basket WITHOUT HEAP. How many tbl spoons? NO TAMPING.
7) Pull the usual shot, time how soon you get the flow.
Stop once the flow color is "beige" off-white.
8) EVALUATE. Any difference in the time vs. empty basket? How 'good' is the resulting brew (bitter, watery, strong, smell vs. the dry grounds) ? Any crema difference vs. direct in-cup brew (color, thinckness, coverage)?
If too bitter, stop the flow sooner (remove the cup). Time it when the flavor is good for your taste. If too accid...your water may be too cold or just let it flow longer.
Is it enough volume for your liking? Personally, a single shot volume (1oz) is not enough for myself, I like sipping it, not shooting.
9) Next, add MORE COFFEE, that is heaping it by one more teaspoon. Still no tamping, just level it a bit, tap-tap, or tamp lightly to fit just below the brim.
10) Do the shot. Evaluate.
Eventually, you'll figure out the amount of coffee you need to fit into your basket and how much tamping needed/possible. Also the results your setup can produce... Hopefully to your taste. And, well, more crema, if that's what your tastebuds ask for, though mostly it's just visuals, unless it's sippable before it gets smeared over the walls of the cup.
Another variation to try is PRE-INFUSION, basically delaying the full flow (if your machine allows you to interrupt the pump). This lets the coffee grounds expand/bloom a bit (3-5sec) before the gushing begins. Just compensate this by stopping the main flow sooner.
Variating the grind is more of fine-tuning, but you'd need a capable grinder. Btw, compare the preground coffee to what your grinder deems 'espresso', chances yours is coarser and dustier.
Anyway, espresso is no magic (mostly), it's just another way of having a taste that you enjoy. Find that taste! Make it repeatable. Keep your taste buds curious :)
Pressurized PF should help your journey, it's kind of equalizer, especially with the setup that you currently have. Espresso should be 'affordable' and liberating, otherwise it's just more viable to buy it directly from a cafe and barista that you like :)