I don't think the rich need to get richer by giving them this break.
I think the main thing that would help would be the elimination of individual player maximums. If a team has cap room and wants to pay Giannis 70 million a year, so be it. Teams also wouldn't feel like they have to give a player like Beal 5 years, 250 million. The max sets the market and sometimes does so on the high end. Without the max, does Beal get that contract, probably not (still paid well, but not some arbitrarily drawn max).
I have in general been OK with the Max contract structure. They have it so that there is a max and a super max. It also changes based on the time the player has been in the league. Maybe they could add some other tiers.
But how about if they allowed larger values in the contracts but only if they were not guaranteed beyond 1 year. So you could sign a player to a 5 years $500M contract if you want but only if the player accepts any year beyond the first as team option. If a player keeps playing well, they keep making a ton of money. If they fall off, the team would have some leverage to either renegotiate or allow the player to become a UFA. You can still get a fully guaranteed contract if you want, but only up to the max contract limits. Basically, similar to football.
There isn't a supermax. It just allows the really good players to have the max contract amount elevated to 1 tier up. No player can sign a contract more than 35% of the cap for the 1st year. And if you are really good player, like Beal, you expect to get the max (which in his case is that 35%). But if there wasn't an individual max, I suspect Beal isn't signing for 35%. he is probably signing more like 25-30%, while a guy like Giannis would probably get 40-50%.
There are two other things they could do.
1 - they could just count all max contracts the exact same for the tax i.e. 30%. Years of service and actual percentage doesn't matter, the contract counts as 30% (and you'd have to have some oversight from the league so a team doesn't sign a guy to 24.9% instead of the 25% max).
2 - they could make the contract adjust based on the cap. So if you sign for 25%, every year you make exactly 25% of the cap. So if there is a big cap jump, the contract goes up a large amount, or if a year like 2020 happens, your 25% actually goes down. Frankly, they could do that with all contracts, such that if you sign for 5% of the cap, the next year of the contract you still make 5% of the cap.