Thanks everyone, definitely helped.
In terms of FFA it is true we are fighting a battle where everything is stacked against us: we have to work harder for meter, our l1 and 2s are junk compared to the best, and our best stages for building meter (the bigger it is the easier to isolate and punish) are the ones Devil Trigger is least effective. I also think, and I elaborate below, that Dante is a very “not strong in killing, but strong in not being killed” character, which is great in theory evading all those lv1 and 2s, but he can only do so much against 3s like Sackboy and Cooper.
In terms of super management you are right, Lv1 is crappy but doing it often is our best bet for winning. The issue is in finding the perfect time in which you get 2-3 kills without getting stuffed (FFA in a nutshell >> ). I still think Dante’s canceling and mobility has great potential here, however, in that where characters normally see “lol a combo sneak and super them” you can cancel/dash behind them and punish their hubris. In fact I think mobility >super punish might be more effective than canceling>super combo in ffas (we get interrupted in our normal combos why should we feel safe in the harder ones?). As an optimist tactics like these may be why his level 1 is so poor in the first place. Need to be better before I can see if theory becomes practice though.
As for Parry I am the opposite: been using it more in FFA but to great success. I am very stingy with it though, busting it out midcombo only when I know there is an incoming square behind me or a super telegraphed move like Nariko/Princess dive bomb. In other instances even though I think Parry might be possible I find it better to air dash the F out of there and stay safe, and if it was a projectile that would hit the retreating dash, I ^triangle above it then dash at them in an attempt to punish with >square and into level 2 or strong combo, ideally (it happened once…).
I am gonna try Dante for another day or two and if still no success I think I will relegate him to a 1v1 main and learn someone more abusable in ffa.