Let's get this out of the way first: I gained strength (after 2 years, so doubtful it was any newb stuff hanging around) on Ostarine, while at -750 to 1000kcals (not Keto though). But you are leery of even the "Gray" side (requires same FULL PCT with SERM/s), cool beans.
What you have, is a lot easier to maintain/retain, than trying to add/build - so I wouldn't be too worried. And the less your deficit (slow cut), the less I'd worry even then. Worst case - whatever you lose will come right back (hopefully not the fat though!) due to muscle/CNS memory. Deloads don't cause strength loss. 14 Days of doing nothing doesn't either. Don't worry, and don't waste money. The only caveat would be if you are going to go Keto - performance will probably drop a bit - but it will come back.
As far as mega dosing Ecdy's etc...
This is as unbias as you are probably going to find. The main copy is probably very exciting, but read the bottom line:
https://suppversity.blogspot.com/2015/12/ecdysterone-beats-popular-anabolics.html
I took 2 bottles of what most would say is guaranteed legit RCE - minor recovery improvements for training already being done, new movements still hurt like hell (DOMS). No "holy sh^t where did that strength come from, and I look HUGE!" to report. Save your money is my advice.