I am happy to hear that you are aiming for PO and SWAT. Improving one's armor is always desirable.
If you are aiming for level 3 (SWAT), you are emulating a specific trooper. That means, you have to weather your armor exactly as in the film model. You also have to build your blaster and backpack exactly as your dream trooper carries them. Ready-made backpacks that are suitable for level 3 are not sold anywhere. The finished packs mostly correspond to level 2 (PO) and look quite good, but you have to consider: There are many special features of the packs from the fil that you have to copy for level 3: damage, certain paintwork, the position of the components.
Have a look at the build threads here in the forum, browse the SWAT forum. If you have a particular trooper in mind, study them. Pay attention to the specifics. How is the weathering, does the armor or helmet have any special features (number of tube stripes, flaking, ...), how is the backpack constructed ...
It's not always easy, but it is an exciting challenge. And when you have level 3 then you deserve it and wear the patch with pride.
Even if you aim for level 2, it is an improvement on the basic level. The armor, the appearance - everything is closer to the film model. And that's what we want. And here, too, your efforts will be awarded a certificate and a special coin.
I would be happy to read more from you in the near future. Don't hesitate to start a WIP.