I can recommend to use DPL Elite with both VP and FP just activated (not separately installed) within DPL. As for Nik… hm… I’d skip it for now. It offers a few niceties, but I feel that they are better suited as plugins for Adobes PS and LR than as an addition to the DxO Photo Suite: https://shop.dxo.com/de/photo-software/dxo-photo-suite
In my early DxO days, I used the standard edition only to find that I had to upgrade to elite a few months later because of the camera I used (differentiation was different at that time). I also installed VP and FP separately and found that a possible benefit would not outweigh the ease of use with all packages activated in one app.
I hope that DxO can get rid of media breaks soon and integrate Nik functionality into DPL.
Filmpack is completely integrated into Photolab, so much so that you would not recognize it as a separate piece of software. I have FilmPack and the Nik Collection and use both with PhotoLab Elite 3. Not everybody wants both of them, but I find having both of them extremely useful.
Elite over Essential, VP is great to have for architectural. FP if you want some film preset.
Nik collection are plugins, like using Luminar, Topaz, Alienskin for example, and your image from PL need (duplicated) to be send as .tiff or .jpeg. I use Nik like many others do, but there is also many that don’t. Best to try first to see if you need any of them.
I installed everything at once PL, FP and VP. I still haven’t been able to work out what functionality belongs to which. All I know is, it makes life very simple when I can edit a RAW file, from beginning to end, in the same app.