I spend approximately 1500 xeno and I have all the cool stuff unlocked and some stuff that I don’t always use (I swap between them).
If you know what to buy and skip all passives+blueprints, you can reach r15 for around 600 xeno (+the 100 initial xeno).
You took the missile reloading as far as I can see. And I guess you took the Thar Ga tok line (with 10% damage at the end) + the r5 motor node + matter absorber, since you followed my build.
These are “powerful node” : Low evo point, big effect but cost xeno.
If you skipped them, you’d be r13 or r15.
Let’s be honnest : The missile reload costs 50 xeno for 40 evo points
At your rank, a slot or a buffer should costs between 20 and 24 xeno.
For these 50 xeno you’d be able to buy 2 slots for 60 each. Just with this you’d win one rank.
Can you give an estimate on Monocrystals spent by your Tharga research? Just a rough number like 200 maybe? Because I think these are the most rare and limiting factors: Xenos and Monos - not?