There is a grey zone, it depends on how much benefit you get from cashing instead of playing the game normally, which is why you don't call it pay to win but pay to progress because after all, anything that is in the cash shop can be bought with gold.
If you want to stick strictly to the definition of P2W then this game isn't it, it used to mean paying for things that benefit you and that you couldn't get via ingame resources, that itself is p2w.
This server IS less p2w/pay to progress than officials because your credits just aren't worth as much and shit is cheaper. Yes that means whales can get shit easier but it also means your average player can also afford those things in time.
I also did some math before in this post:
https://na.archerage.to/forums/index.php?threads/p2w-rng-boxes.1572/page-2#post-13709
Basically it boils down to 12h ingame for me equals to 100$ worth of credits. (Prices before donations went down. And the silver per labour wasn't exactly that good either.)
Which kind of invalidates your example of 20$ = 16h because you're clearly not doing anything profitable in those 16 hours.
The reality of it, imo, is that people don't want to bother actually finding a profitable source of income. Maybe they get bored, who knows.
And since they can't be bothered to actually get gold ingame they drift towards complaining how people that pay can just get ahead of you. (We all know how easy it is to complain about things.)
I mean, shit, if 100$ for you is worth that little then by all means go ahead and spend it, support the server.
Meanwhile I'll stay f2p and keep playing the server for free while still being able to compete with your average player. (Maybe even above average. Not the top players for sure though.)