Diablo 1 was a very finite progression roguelite.
The decline set in D2 where it tried to take turn it into an infinite progression MMOLite Skinnerian grindfest.
In D1 you had to adapt - to the finite stuff you found, finite stuff you could buy and to the (thankfully also finite) enemies that were randomized.
In D2 you could just grind diablo- and later bhaalruns until stuff you wanted fell out, so you could complete your dream build(TM).
TBH D2 is also badly inflated, especially itemization.
I reached level 50 with my necro on NM. I have +3-4 all skills and some items with +3 on some other skills. Amu, dagger, OrtSol, shield, that kind of thing.
There are a HUGE difference between D2 post runewords inflation to D3 inflation. D2 inflation is more akin to modern Argentina, D3 inflation is more akin to Weimar Republic or maybe Zimbabwe inflation. Even with all OP runewords of D2, i never saw a build dealing more than 30k damage while on D3, you complete a set and start to do dozens of millions of damage
So what you're saying is you want the difference between playing for 1 hour and 50 hours to be not quite doubling your stats.
See dark souls, is the ARPG with best character progression that i saw. Most stats has diminishing returns and leveling up becomes much more expensive.
Progression via number inflation is the least kind of progression. Progression via added capabilities is better.
HP and damage/DPS is the least kind of number inflation.
If you have to progress by number incrementing, you need a cap of some sort.
Numbers only mean anything in relation to each other.
When your numbers are 9 fucking orders of magnitude from one another they no longer relate meaningfully.
For energy this is about the difference between an assault rifle bullet and a fucking Hiroshima.
For range it's about the difference between a rat's bite and an ICBM.
This is not the kind of numbers that meaningfully relate to one another when put on supposedly the same time of objects (like sword VS sword).
IF you do need to have infinite progression, you can base your mechanics on opposed stats.