Diving into a lot of different training content, an interesting concept I've come across is incorporating non-standard lines (where there is no ev loss) vs regs to bring them to areas where they will react poorly.

E.g. Weird sizings & non-standard donks - In particular, looking for spots where the solver response isn't intuitive.

What I'm trying to grasp is if this is a good idea for me to take time figuring out now, or if I should just tuck it into the back of my mind well into the future.

For context, I just recently moved into 5NL GG R&C, and am breakeven post rakeback.

Any general thoughts on when (stake wise) people have seen this incorporated in their own game or other regs' games would be super helpful for me to understand how to prioritize learning this.

At 5NL I wouldn't really be worrying about trying to outsmart good regs, I'd either be

a) Not getting into games filled with them in the first place
b) If in games with them, not trying to get involved in pots with them where possible/marginal and concentrating on exploiting the bad players

While what you suggest does make some sort of sense, nobody in their right mind is using solver outputs by rote, they would be using it as a baseline as to what they think is theoretically "correct" and knowing the adaptations to make if the opponent deviates from said strategy. It's not like chess where you might be able to get a better player in trouble if you get him out of book in the opening