The RTTS "manager", heck, the entire system, is barely coded to "take advantage" of the full potential of two-way players.
To wit:
SP/XX (any fielding position) combos are all "you do nothing but pitch" on your designated rotation day, it does not take advantage of allowing you to hit in the same game you're pitching.
I played a SS/CP myself. Even in the minors, it was "oh, this dude needs to pitch (soon). Start giving him days off till the team needs it's closer / he has to pitch due to too much 'layoff'". After that pitched inning, would go back into field until the "dude needs to pitch soon" logic caused this cycle to repeat.
Honestly, I'm not sure how, or even if, the Ohtani Rule (pitcher can DH in same game) would work with relivers. Remembering that the DH "goes away" if you sub that player out of the lineup, once you "switch" from SS to pitcher, the game would have to either leave the starting DH in (preserving the spot but ending any chances for you to remain in the batting lineup) or "double switch" you to pitcher and have the "replacement SS" sub into the DH spot - killing the spot if the game goes extra innings.
H