Also, I just checked, I purchased Mark II lifetime and got Mark III for free. It's only Mark I users that didn't get it.
Unfortunately it looks like lifetime users don't get access to the beta program for whatever reason. I guess they don't want feedback from those users.
I tried Analogue too, but I stopped using third-party camera apps altogether because they all seem to suffer from an issue where if you lock the phone too quickly after taking a photo, the photo is lost forever. I lost so many photos to this that I knew I took.
Apple limits TestFlight to 10,000 testers. Folks who are paying a recurring fee expect to see more frequent updates, so they get priority.
Halide shouldn't be afflicted by the lost photo issue you're talking about. Normally, if you close a lock-screen extension before a photo is written, it won't be in your library. This can be a problem when the user quickly smashes the capture button and your photo queue gets backed up.
Luckily, the unlocked app gets a chance later to access the content of lock-screen capture sessions. So our strategy in Halide is to write the intermediate files to disk as soon as you initiate a capture; this should take a split second. When we have uninterruptible time, later, we make sure the photo finished writing to your library, and if not, we try again.
However, Apple's documentation isn't clear if the OS will "wake-up" your main app to process unfinished photos, or if it relies on the user launching the app. I'll just say that I dog-food Halide every day by capturing photos of my toddler, and I can't remember the last time I lost a shot.