this was actually really helpful, thanks for posting.

Just adding something I’ve been using lately, a website converter can be used as app on iphone.

It’s basically a HEIC → JPG converter, and the nice part is you can save it to your Home Screen so it feels like an app (no need to keep typing the site every time).

Also random iPhone gotcha: if you pick images straight from Photos, iOS auto-turns them into JPG before uploading, so it looks like you “converted” when you didn’t. If you want the real HEIC files, move them into the Files app (the one you mentioned in your post) first, then upload from Files.

Anyway, it’s been great for big batches and feels pretty private since it runs locally but not sending my photoes to any server, because safety is first.

the website is heicjpg.net