US citizen abroad on FEIE – Am I missing/overthinking something with IBR/PAYE vs RAP?

Hey all, I'd really appreciate some input as I don't have anyone in a similar spot to use as a sounding board.

I live abroad, and file the FEIE every year on my taxes. My AGI is $0. All loans are federal, and balance is $40k.

I graduated end of 2017, had my repayment grace period, went right into an Americorps year so they were deferred, after that ended in 2018 I went onto the REPAYE program, then moved abroad in 2019. I recertified my (foreign) income in 2020 days before the Covid freeze, so never ended up paying even thought the repayment was fairly low from memory, then was put onto SAVE when that came into effect, and have been since.

Other things that may be pertinent: I left before I could pay into social security long enough to get it in the future, I have immaculate credit, I received Pell grants, I'm in a de facto partnership so legal implications of marriage aren't an issue, and I've taken care to set myself up in such a way where I have essentially nothing but the bare minimum to report on my taxes. I make a normal amount of money with no huge salary jumps expected – enough to have to consider this smartly, but not enough to feel like a dedicated accountant or financial advisor would have any practical benefit.

I'm fortunate to have dual citizenship, and have no plans on going back to the US. I suppose if worst came to absolute worst, I may try and find a remote job for a US company, but if that were to happen, I'd expect that whatever income I would be making would be worth whatever impact that would have on repayments, since the exchange rate would be highly, highly favorable.

Regarding repayment: I was thinking about cashing out non-emergency fund savings and paying down in lumps when the exchange rate is beneficial maybe once a year or so. Either that or instead opting to save for the tax when it is forgiven in the future. Is there any way to calculate what the 'tax bomb' would come to?

Now that REPAYE is gone, and PAYE is the closest replacement, it would be a bummer to have my repayments be calculated on take home pay, since the exchange rate isn't great. Yes, they take the exchange rate into account, but it doesn't account for fluctuations. Not sure if there is a benefit I am missing for why I'd choose this over RAP, other than the reduced time to get forgiveness?

It looks like RAP is the way to go, but I'm not sure if there's any blind spots I'm missing.

Thanks heaps. I'm beginning to parse it out, but would appreciate any other perspectives.