The formula for level requirement XP is 2% more than the previous level, and seems to hold in a straight line from L0 through to at least L210 with only minor rounding errors. That formula does not seem to have changed despite the amount of XP we can earn being reduced 75%.
I can completely relate to that feeling. With the state of the game now I feel I cannot make any progress and it is killing the fun of the game.
Progress from the Citadel has been killed with the XP nerf. I now measure my progress there in weeks per Citadel level, not levels per week. Any individual level gain there is also a fairly inconsequential increase, that may be of no use to your preferred class(es). So progression here is virtually zero.
To level faster means playing more, but there hitting other caps - chest limits, gold/food/ore caps, storage limits - that mean scrapping many rewards is the only way to keep playing.
To make progress with gear - if I find something I want to keep I inevitably have to scrap another item to make room for it - deciding between good colour Rares vs not ideal Epics just to make space. Upgrading and evolution is held back by Glyphs which don’t drop and Relics which don’t drop more so than the drip feed of higher rarity shards.
A grind that results in some progress can still be fun. But a grind with no sense of progress isn’t. Grinding the old goals system was an example of that where I wouldn’t have chosen to use specific weapons for 100 runs each, but there was some reward at the end besides the loot (99% instant salvage). Then the update wiped out that and replaced it with a new system, new grind, but also greatly reduced benefits.
It feels more and more like each area of the game is being designed in a way to stop or greatly slow any sense of progress.