pay for advantage was an okish concept 15 years ago but in todays gaming industry its usualy frowned upon and having the game tagged as "pay to win" is one of the worst reviews a game can get, thats why most games (at least the ones i am aware and that are doing more or less well) get their money from more ethical transactions such as vanity items (transactions that only affect appearance) or quality of life improvments (bigger backpack, shared bank between chars, increased exp gain,etc..), third option is to add advantages on the shop but make it in a subtle way so it dosent feel like buy this or prepare for hell, world of tanks did a good job with the third option, they added strong but very expensive things that could be bought with ingame money (crit in DR case) giving people 2 options, playing good to maximise gain per game so they can sustain this items or pay for prem time wich increased the gains.
path of exile for instance made a lot of money from selling cosmetical things, fancy pets and stash tabs. heck they have 2 packages, one of 1k $ and another of over 10k $ that alow people to add a unique item /monster of their choice to the game (after proper balance) and people buy the 1k package all the time plus i saw like 3 or 4 of the 10k ones too.
whats more important a more ethical shop will encourage the so called freeloaders or people who dont pay to play the game wich is a good thing becouse they are the ones who fill the servers.
my 2 cents on this:
-only leave on the shop exp pills and cosmetical items
-remove durability loss when using shop repair, this will replace repair hammers aswell as create crit sinks, if needed increace repair cost of high grade rares or even better rework the way durability is lost so is not only the tank the one with a large bill.
-add fame shop and fame pills (will explain latter)
-add to the shop skin transfer (swap item apearance while leaving atributes untouched), may be even add that for a large price they could get a permanent statue with a dedicatory of their choice (becouse we know someone will buy it just to put "in commemoration of "x" kicking "y" butt
)fame shop
fame shop will have all the laser, sards, amulets, capes, sadles and the likes previusly removed (wont have red envelope becouse logic) but instead of asking RE it will ask fame or dual fame depending on the item. this creates a fame sink, promotes people to actualy fight even if they are already d4 and is a subtle way to encourage spending (fame pills )without forcing it.