Another version of the count-up idea, this time down and mechanical. SPOILERS. Though this is far more lenient.
https://drive.google.com/file/d/1aeCT-0ti2mw-qqPQixH8zjHQ6s0fML5a/view?usp=shari...
(Spoilers for "Counting to 10" and "Countdown's revenge"; use ROT13 to decode)
Gubhtu lbhe chmmyr vf hygvzngryl gur fnzr chmmyr nf zl irefvba (fnir sbe znxvat vg rkcyvpvg gung bayl bar hfr bs gur erfrggvat qbbef vf npghnyyl urycshy), V guvax lbhef qvq n orggre wbo ng ivfhnyvmngvba; culfvpnyyl fubjvat gur pbhagvat sebz 1 gb 10 ivn gur checyr qbbef vf fbzrjung htyl, juvyr lbhe irefvba znxrf gur pbhagqbja srry zber angheny. Vs lbh unira'g nyernql cynlrq Pbhagvat gb 10, gura Pbhagqbja'f Eriratr vf n irefvba jurer vg'f n yvggyr uneqre gb svther bhg jung fgrcf lbh npghnyyl arrq gb qb orsber lbh trg gb gur npghny chmmyr bs svthevat bhg rnpu vaqvivqhny ahzore, naq fvapr Pbhagvat gb 10 vf bar bs gubfr chmmyrf jurer Ybpxcvpx'f zrpunavpf ner zber bs n pbng bs cnvag sbe n zngu chmmyr, V guvax vg'f svggvat gung svthevat bhg jung gur tbny vf vf cneg bs gur onggyr, nf gung'f ubj bgure chmmyrf yvxr guvf jbex. Gung orvat fnvq, V qb guvax vg'f orggre vs gur chmmyr pbhagf hc vafgrnq bs qbja, fvapr gur uvture ahzoref unir zber pbzcyvpngrq zvavzhz-Znfgre Xrl fbyhgvbaf.
Another version of the count-up idea, where you only have to count up to one number.
https://drive.google.com/file/d/1Za9gBN7sp4Sqv_nsXWGb3A4kaYEsv3j5/view?usp=shari...
Wow, that's a big number. I honestly don't know how to do this one; solving these count-up levels tends to be trial and error/intuition based, and with a number this big, it's unrealistic to do the trial and error method. Perhaps I'll figure out a trick to this at some point, but there's a decent chance I'm not gonna figure this one out.
I went and crunched the numbers on it, there are technically quite a lot of solutions, some even doing better than the given Master Key count. There's a lot of layers to unpack, but there is a general strategy for this problem which, while not giving the perfect sequence (as there are several), will still give you something good enough to solve it.
Well, that was maddening.
The good news is I can definitely solve other puzzles of this kind assuming similar tolerance levels. However, you said there are more optimized ways to solve this level, and I don't know if anyone could find the most optimal solution on purpose.
I need a special cipher to encode the solution. Convert 939482453 to binary, then execute the resulting instructions as green=1, purple=0
Right back atcha:
https://drive.google.com/file/d/1Hh5D_eK1zYRdEfNniZyFKqmhYT3Jw-3N/view?usp=shari...
I'm back, and I made the level you feared!
https://drive.google.com/file/d/1CzkiYlgZ6qBw_JTzdzQALTW01TVKVFPG/view?usp=shari...