The one you bolded in your original post about warrior-types being advantaged because they could save money spent on striking runes to spend on skill-boosting items.
Right.
So, if I understand your question correctly...
Wouldn’t only the variant with just devastating strikes have that problem (with skill-boosting items)? The one in the GMG gets rid of all items bonuses except for armor, which includes skill-boosting items.
...you're asking if reducing ABP to devastating strikes only leads to a problem with warriors being able to purchase more skill-boosting items?
I think we're mixing two separate subjects.
I was talking about a reduced ABP to point out that it really is only the striking runes that occupy this triply uncomfortable place where they're a) totally expected by the game's math, yet still not given out automatically b) you really have to give them to your players and c) they far outshine all other magic items. I'm assuming ABP exists because people find the default implementation inelegant and still reliant on items (a vestige of the woes of PF1). If so, the part of ABP you really really need is devastating strikes.
Something like a weapon potency rune meets criterias a+c but not b. So you might still want to have ABP replace potency runes, not because you have to, but because they're too good compared to most other items. This does, as stated, help warriors, not casters, so one problem leads to the next...
The other thing I said was about how striking runes only affect warriors, and so not having to purchase them (because you get devastating strikes for free) frees up a lot of money for other stuff, advantaging warriors compared to casters. If you want to fix this, you need something like having striking runes be useful for spellcasters too.
I haven't suggested reducing ABP as a solution to the warrior-caster imbalance. I discussed reducing ABP because I feel that's a
better ABP, one that doesn't remove more of the magic item economy than it absolutely has to. I realize you could infer there was a connection, but please read my thoughts on ABP as a sidetrack or rant. It was brought on by your mention, but not really germane to the main gold for XP discussion.
And of course, ABP came up when you suggested ABP as being better than PWL at fixing the rather PF2-specific issue where nothing you can purchase comes close to a level.
I would say PWL is damned near mandatory for an XP for GP campaign with a functioning magic item economy where the same gold purchases everything. Another way of saying this is that the level you add to proficiency makes it impossible to mix gp and xp. If you run a game where gold can buy you xp but nothing else (i.e. you're running magic items much like 5E rather than the default PF2 system) you don't need to do anything, of course.
Using ABP on the other hand is retreating from a fully functional magic item economy, since far fewer items are left to exist in the game. Since you remove pretty much all the really worthwhile items, I'd say ABP amplifies the problem instead of mitigating it. If you can't even purchase a skill bonus (let alone an extra weapon die) you damn sure won't part with a penny that doesn't go towards XP...
I hope that was on topic. But I'm not 100% sure...