Okay, as a disclaimer, maybe I haven't tooled around in the settings to get things the way they should be for something like this.
But overall? This is really aggravating me as a new-ish player on console when doing the New Strange synthesis scanning on Ares/Mars: I can't effectively set the trap(s) and then scan the target in enough time, as by the time I lay the trap and then get into the gear wheel to select the Synthesis Scanner and then start scanning... the trap stops and then the Elite Lancer uses the forcefield to push me several feet away and then runs off. Repeat this at least several times and/or until the traps run out.
I don't mind a good, fun challenge, but strictly IMHO, there is a clear difference between a legitimate challenge and broken-ish mechanics (due in part to console limitations, I know) that turn it into a "frustration challenge" rather than a "fun challenge". (Example: Hijack is a "fun challenge", since it makes me think more clearly about what Frames/Mods to use to maximize potential for success)
I get that one of the limitations of being on a console is that we don't have extra keys/inputs like PC players do, and I willingly accept that. That said... I think it would help greatly if there was some way in the Arsenal menu to assign an item to the Hotkey input (i.e. D-Pad Up reassigned to Hotkey 1 = instantly lays a kinetic trap down, D-Pad Left reassigned to Hotkey 2 = equips Synthesis scanner), that would make this quest a lot less frustrating for some. Again, unless I'm missing something (and it could very well be the case) and you can already do that on Switch/XB1/PS4.
Alternatively, I guess the other option is to spend even more time grinding by doing bog-basic Synthesis scans to get the standing to buy the sigils (that supposedly reduce scan time/multiply scans/etc), but ughhhhh. If there's no other alternative, I might as well have to do that.... or if this is something another player can help with, I dunno. :T