I beat Persona 5 Strikers 100%, at least as far as I'm concerned. I finished the game, got every recipe, and completed every sidequest, even the Reaper boss battle. There are four Personas that I haven't summoned yet, five if you count Lucifer who's only in New Game Plus, and a few Bond skills that I haven't maxed out yet, but those seem minor by comparison.
I really enjoyed the game - it felt a lot like Persona 5 despite being a wildly different genre, though towards the end, it felt a bit too self-referential (to the point where the characters were outright saying "this is almost exactly like what happened last time!"). I'm really glad that I stocked up on items for the extra difficult shadows like King Frost or Mara, where you have to beat them to get the ability to summon them, as well as the bonus boss who you need to beat to unlock New Game Plus.
The character interactions were the highlight for me; it felt like I was playing Persona 5 all over again. It took me about 46 hours to beat it any unlock New Game Plus (putting it in the top ten for my Switch games in terms of time spent on it), but the time just flew by.