"It's not a powerfantasy in the slightest"?
sure rowan isn't going to dominate the twins as soon as he arrives in the castle and they generally make his life hard. but no powerfantasy?
he is simultaneously the best strategist, has an unbending will to surpass a master sorceress's magic while also attracting interdimensional beings with it, can control sex demons with his sexual prowess, has far reaching influence over nobles and peasants alike, is the most skilled non-magic user to ever exist, is the most valuable asset in the entire chaos faction, and is able to run a small government without the access to excel (who knows, maybe luirial is the magic equivalent to excel
)
oh, and before i forget he still finds time to fuck constantly!
and you think rowan isn't overpowered like a gary-stu?
since you want to avoid andras ntr: you should DEFINITELY "invite" her into your room. there is no non-ntr progress with helayna if you don't claim her! (at least if you consider helayna being used as communal fuckdoll as ntr).
besides claiming helayna isn't that bad to alexia's relationship if you tell alexia rowan couldn’t stop himself. and you lose on one scene with alexia in total only.
as for alexia scenes in general, you get certain scenes depending on her corruption level and current time. my advice is to have a relative pure alexia in early game (till around week 40) and then amp up the corruption afterwards (with events like fertility treatment for example). other than that, just have her relationship points high at all times.