Blue
Ravenous Bugblatter Beast of Traal
Just to look at an out-of-the-box solution, have you tried a less crunchy game with the group? Maybe OSR if you want to stay D&D-like?
The first player seems to want to do cool things, but casters in 5e require internalizing a lot of different specific spells to be able to chose what's correct quickly. A different system might constrain choices in a way that speeds them up.
The second player, well not remembering how his own character works sounds like either the complexity is getting to him, or that he's using outside resources to build characters and not retaining it. Either way a more straightforward system could be a solution.
The third player not paying attention may just be a symptom of the first two - when it takes forever to get back to your action you get bored. And since it sounds like you play online since you mention FG it is really easy to start surfing the web or otherwise get distracted. If this does happen to be the problem it is both the easiest to understand but potentially the hardest to fix since it needs to address the slowness between turns and the habits of disengaging they have built up.
The first player seems to want to do cool things, but casters in 5e require internalizing a lot of different specific spells to be able to chose what's correct quickly. A different system might constrain choices in a way that speeds them up.
The second player, well not remembering how his own character works sounds like either the complexity is getting to him, or that he's using outside resources to build characters and not retaining it. Either way a more straightforward system could be a solution.
The third player not paying attention may just be a symptom of the first two - when it takes forever to get back to your action you get bored. And since it sounds like you play online since you mention FG it is really easy to start surfing the web or otherwise get distracted. If this does happen to be the problem it is both the easiest to understand but potentially the hardest to fix since it needs to address the slowness between turns and the habits of disengaging they have built up.