i'm not a gundam fan so this is purely about the question of what is and isn't bait, and i do think intent matters a LOT. and it can be difficult in many cases to tell, because very often we don't know the behind-the-scenes of any given work.
my take is that subtext becomes bait when they could commit, but instead go for the "plausible deniability" thing for demographic and marketing reasons. a clear example of the latter is love live, which toes the yuri line just enough to rile up shippers without ever actually being romantic. framing here is really important. if the subtext people point at is all fanservice, casual physical affection, or Super Best Friends statements, chances are it's bait! and imo bait itself isn't a bad thing at all so long as you know what you're getting into -- and that includes scummy rug pulls from canon.
subtext that is not bait, however, resembles straight romance in framing and writing. an easy example i can give is clannad's anime, where they're never shown kissing, and all the romance and love is in those small gestures that are given immense weight. this isn't to call clannad itself subtext, but to say that sincere subtextual yuri follows the same cues.
one case i enjoyed is in fresh precure, which has this scene where setsuna (in a moment of peril) calls out love's name... and love immediately wakes up from sleeping, implying this soulmate level connection. over in aikatsu, ichigo and mizuki's relationship is such strong subtext that it became text and bamco made them backpedal (because they're homophobic). secret moonlit meetings alone together, mizuki's name for her gradually changing (ichigo-chan -> hoshimiya -> ichigo) as it develops, and all the writing in season 1 that framed them as something fated and perfectly matching. good subtext doesn't need to say "i love you" out loud to clearly show two people in love.
i probably wrote too much, but... it's something i think about a lot myself, so hopefully i'm making sense here lol
I think you're making sense. It's also a matter of perspective and opinion, people will view things differently and use words differently. In your case it sounds like you use bait a lot more than I do, for example you think Love Live is bait and I don't. I know Love Live won't have canonical romances but will provide solid fuel for fan artists to work with, to me that's not bait as I'm not getting baited by anything, I'm merely consuming media where I know my reaction will be "their relationship is cute and I can easily imagine more". For me that's more so a branch on the tree of subtext. I'd only use bait if Love Live introduced men that came in and swept the girls off their feet after the series produced all of that relationship fuel between the girls. Along those lines it's why I generally view bait as a negative term and typically a bad thing. As media that wants to reel you in with a promising same sex relationship but then swerves into a hetero one feels like a homophobic "gotcha" to me. So I think all of these terms are various cases of millage will vary.
Reminds me also that in my opinion Flip Flappers is Yuri, a lot of subtext though I thought the relationship was clear. Yet I saw another case today where people were calling it bait, and personally I found that frustrating. Alas though, arguing is generally not worth the time. I have my views and others have their views.