i noticed that 1 mat is lacking if i play all features of the game, including the cube and Myriam:
-namely the white mats (Reusable Parts).
-those are farmed about half the number they should during general gameplay. 
A screenshot of my non-seasonal materials, taken a couple of minutes agoâŚ
https://i.imgur.com/cm137PF.jpg
White - 552,715
Blue - 587,781
Yellow - 587,757
If the ratio youâre claiming was true, I should have around 293,890 white mats.
your âgeneral gameplayâ could differ from mine;
-iâve alot of gear to get to ancient, for instance. 
Non-seasonal, itâs usually just Nephalem Rifts for keys and GRs to level up gems, i.e. I do very few bounties, as youâll see from the numbers of bounty mats.
If youâre attempting to get ancients, I presume you mean via the Cubeâs âReforge Legendaryâ recipe. In which case, that uses Bounty materials and Forgotten souls, i.e. doesnât doesnât involve white / blue / yellow materials at all.
If youâre using the Cubeâs âUpgrade rare to legendaryâ that uses exactly the same amount of white / blue / yellows per upgrade and wouldnât account for a discrepancy.
If youâre really stuck, however, do some runs of Act V, Battlefields of Eternity and click on all the armour racks. These generally drop white or grey armour / weapons, and they salvage into 8-12 reusable parts. So, a 2-3 minute run around the map gets you an inventory full of white items, some of which will be belts, so youâll get more than 30 of them. You should easily see 300-350 white mats from a 3 minute run.
Alternatively, use the Cubeâs recipes for converting blue or yellow materials to white.
yes, i know this farming spot;
-itâs during upgrading and tweaking gear, that my whites get hit about twice as hard as my other mats.