I thought I would be ready to install my engineered wood this weekend, but

Can't seem to get level in both directions. Using level quick. Using a 10' aluminum boxed screed to check for low spots (4 seperate bedrooms)

When I get one direction good, checking the other way, it's off. There are lower perimeter areas, plus various lows in every direction. It is frustrating to say the least.

If this were a depression, it would be simple, fill and screed. But it's not . I'm beginning to think the entrire floor should have been leveled at one time, I'm ending up with that, but piecemeal, making for problems.

What tools should I be using? Would a gauge rake work, or is that more for entire floors? What am I missing?

I work on any high spots first, what is your substrate?

Ya, it sounds like you didn't attack the high places where the screed teeter-tottered, first, before you started to drag some mud.

Now your chasing it.. Typical rookie mistake. We have all been there.

Substrate is slab on grade, 6 year old monolithic slab.

Yeah, I see the problem, if the high spots are scattered in the field, then the low spots aren't really low. Next time I will NOT poor any leveling compound until I am 100% sure that at least the high areas are down

Any suggestions on how to proceed besides carpeting or moving

Yes sir, I have done the same thing. I believe I would map out the floor marking all the high and low spots. Get rid of those teeter-totter high spots by chiseling, grinding, scarifying , or moving

Re-map the floor again and some of the previously marked low spots will have magically disappeared. What low spots are left you would then fill with a cementitious patching compoud.