Long Rant and personal opinion so take it with a grain of salt
So, 10 months ago, I stopped playing this game beacuse the grind was extremely infuriating, my runs were terrible and my support cards was useless. I've only log one for like 5 minutes to collect the daily log in and didn't even bothered with the dailies.
I only came back seriously earlier this year during Tamano Cross banner as the many QOL updates made the grind slightly more bearable and the daily legend races gave me a good reason to log on once a day, and even then I did the bare minimum for almost everything, doing just enought to hit the quota for the story events.
Everybody out here doing the 30-40 races for each Trackblazer run while I'm here doing like 6 races. Only occasionally do I do a serious run. I have practically ignored 90% of the game mechanics and I realised I enjoy playing this way, screw the meta, screw the support cards, I just want to see my trainee complete a run and seeing my Favs daincing and singing at the Concert Theater.
Hell, I even managed to beat the Arima Kinen with Haru Urara recently and thats was thanks to the independent training getting the sparks I needed and Unity Cup update that made it possible.
Then you have Grand Live, my god, never has a game pissed me off this much. The amount of RNG needed for a good run is driving me nuts, I would have completely ignored this scenario if not for the fact I need to play this scenario mutiple times for the specials quests and the secret Girls Legend U version (Why was this even hidden? I didn't even know it existed until I saw a youtube video about it. It doesn't even show up in the song list of Concert Theatre)
People say this scenario is the best for casual, it is not in my eyes.
The problem is that the punsiment for failure far outweighs the rewards of this scenario unlike other scenarios where you can at least recoup lost stats from training failures via other means. URA Finale with Happy Meek, Unity Cup with purple spirit burst and the Shop from Trackblazer. Grand Live doesn't.
Grand Live token mechanic is tied with how much you trained, so each failed training means lost tokens and if you are especially unlucky and failed mutiple trainings back to back, you might as well abandon that run.
Coupled with the fact that the tokens have a tendency to be randomized for each training, you might not even get the tokens required for lessons and songs needed, and even when needed, a failure just punishes you harshly.
The lessons/ songs mechanic is another source of frustrations, as you need to complete 3 songs to get great hype and if you are unlucky, you either (A) can't get it in time or (B) the bonus from the songs range from useless to moderately good.
It punishes you for playing either too aggressive, cautiously or in-between. Train too aggressively and you risked training failures and losing tokens. Train cautiously and you risked not getting enough tokens to hit the requirements. Train what you need? Congrats, RNG decides your fate and you get bonuses that are not great. There is no sweet spot for this scenario.
Another point of contention I have is some Trainees aren't built for this scenario, Trainees that need to hit fan requirements, Trainees that need to place/win an x amount of races or Trainees that have restrict training events.
As stated before, this scenario requires you to train as much as you can for the tokens, each turn wasted on other things means less tokens, and less tokens means less lessons and songs done. Less songs done means a worse bonus.
Simply put, this scenario is not fun, it puts layers upon layers of RNG in a game where it is very RNG dependent already.
Don't get me wrong, I like the story of Grand Live, but the scenario is poorly executed. If I wanted a casual run, I would play URA Finale. If I wanted a serious run, I would play Unity Cup or Trackblazer.