Well I really don’t like this answer but:
Time will fix your frustrations. Especially if you have more than average skill or can develop it.
Time in game is the only thing. I have over 5 years of collecting parts.
I understand your frustration. When I started, under 2400 ps was full of people with Harvesters. Those were my version of the problem you have. Not enough gear to respond to players that have the gear and efficient builds. Time (or money) will fix that. At least XO lets you choose your input.
I can tell you, of the time I have played, looking back, it was really not that long until I was competitive in relation to the total time I have played. (and yes, I know this doesn’t help anything)
Have you played in a squad or have any people you play with?