Well, it seems to me you're getting several concepts confused.

First, "bump" in the freuquent flyer world means getting a (hopefully voluntary!) denied boarding voucher on overbooked flights, and those people who are "looking for bumps" are looking flights which are likely to be overbooked on which they will be offer vouchers. I has nothing to do with upgrades.

Second, using a different terms confuses yourself because you don't distinguish between the different ways of getting into the front cabin.

Next, American has both points and miles and three types of upgrades, and they all work differently for different people.

Without flying 100k a year (or finding double EQM promos on which you can do oodles of mileage runs), you're not likely to get the top status level where you get SWUs (system wide upgrades), so let's forget that for you.

Next, there are upgrades with miles than anyone can do, but if they're flying on a paid flight. So what confuses me is your mention of Amex points. Does AA consider that a normally paid flight, a consolidator paid flight, or an award flight? If it's a consolidator paid flight or an award flight, upgrades of any kind are out. So only if these look to AA like normal paid lfights (just paid by someone else) can you even look at upgrades.

Next, does paying with Amex points let you attach your AAdvantage number? That is further more a requirement for any upgrades.

Ok, now we're up to the two kinds of upgrades you can use:

1. No matter whether you have status or not, you can upgrade with miles + co-pay. But unless you only book flights iwth upgrade availability at the time you book (which you have to use ExpertFlyer.com to determine, a subscription site), you're going to be on waiting lists, and with no status you're not necessarily going to "win" too many of those.

2. If you have status (at least Gold), you can use 500-mile upgrades (formerly known as "stickers") domestically (and a few nearby outside-US destinations). But if you only have Gold (earned with 25000 Elite Qyalifying Miles), you'll be in the lowest pecking order, and you'll rarely "win" too many of those. If you can get up to Platinum (which requires 50000 EQMs) you're "win" more of thse. (But EXPs, who flew 100000 EQMs or 100000 EQPs -- elite qualifying points -- a year, will still always be ahread of you. Perhaps it's the 100000 EQMs that so many earn that those people meant when they say it's ahrd to get upgrades because of "so many points"?). Btw, points can only be earned through fliying, and only through fliying on more expensive fares (no discount economy).

Finally, at most airlines (including AA), credit card spend does not help with anything other than mehtod 1 above, miles + co-pay upgrades. Credit card spend does not earn Elite Qualify Miles, so doesn't help you get ot 25000 or 50000 miles. (Delta is the main US airline with a bit of an exception to that, but reserach carefully before you decide to switch to Delta just because of that.)