Capital Games TeamEverything you've listed above does not really get to the core of the problem in my opinion the best thing you could do is unlock new abilities or bonus effects at different relic tiers.
This would stall your scalability problem long-term and short-term additionally would make higher relic tiers more viable and more sought after.
As a basic example let's take Malik for example. You could simply say relic five when he's critically hit he applies fear on the Target that hit him plus one random Target.
Then maybe at relic 7 when he's critically hit fear a additional opponent.
At relic 9 when he drains an opponent he gets a Max health increase.
At relic 10 he takes a flat 30% damage reduction.
This is just one example of making simple abilities more effective at higher relic tiers and they unlock when you hit those reluctairs as opposed to needing to buy a new ability material.
And it doesn't have to be that simple it can be way more complex depending on the character I was just trying to keep it simple for an example here.
If you do implement this the one thing that you should not do is lock the bulk of a kit behind The relic levels because that'll just **bleep** off the community as well.
Then you can continue with your linear progression system of one relic level every you know 3 to 5 years and then just add special abilities on top of it with massive scaling on those characters. Problem solved community happy