Backmarket

I got my daughter an iPhone SE (2016) off Swappa about two years ago. She's had no issues with the battery. The seller posted a pic of the battery health, so that swayed me in their direction. I think I spent $90 on the phone, so I'm a fan of Swappa.

Older people like buying from Best Buy because they can always return to the store when they have tech issues.
Best Buy is selling refurbished iphone 8 for $250

I bought a used iphone 8 about two years ago from Amazon. I just replaced the battery last month. I can't imagine any used iphone 8, at this time, not needing battery replacement.

Amazon refurbished promises at least 80% battery life in their used iphones. I am not sure how you would measure that in a meaningful way.

I had a really good experience with Backmarket. I bought my son an iPad mini that died during the warranty period and they refunded my entire purchase.

Long story short, I need to get an Iphone 8 for an older relative who needs an upgraded Iphone but really needs to get one with a home button. I want to buy one at a reasonable price, I recognize that I will likely be buying used/refurb, but want to get one with the best possible battery. Buying direct from Apple would seem to be the best but is rather pricey. I am leery about buying off of swappa, amazon etc. because I want to be sure that the battery will last a while.

Should I just use swappa? Buy from somewhere else?