Painless way of moving from snapshot to release version?

[kingrun]

I want to move some of my routers to different versions of OpenWrt.I usually use the firmware selector here: https://firmware-selector.openwrt.org

For context, I have two routers:
AX3600 running the Snapshot of OpenWrt and I want to move to the release version.
https://openwrt.org/toh/xiaomi/ax3600

Archer C50 V6 running a V4 modified version to work on V6. I saw that there is a V6 snapshot version available.
https://openwrt.org/toh/tp-link/archer-c50

My idea is to do settings backups for both to have all the settings/customizations intact. I need to somehow get a list of all the packages installed so I can build the images with the same packages. Not sure how to painlessly get the list.

Does anyone know of a painless way of doing this if possible via sysupgrade and not having to resort later to unbricking the routers through recovery?

[maurer]

https://openwrt.org/docs/guide-user/additional-software/imagebuilder#selecting_packages

[fakemanhk]

I don't know if it works for all platforms, but for example when I upgraded my Google Gale from snapshot to 23.05.0 release, I installed Attended Sysupgrade package then update from there, it helped me to preserve most things from a running setup.

Of course, if your snapshot has been deployed too long time ago, there might be huge change between versions that could have issue, but for me the snapshot I used VS release version was about 1 months.

[kingrun]

Thank you was able to update without much headache by providing the installed packages in the builder. Afterwards installed the attended sysupgrade for future updates. Should work like a treat. Thank you

[maurer]

If your problem is solved, please consider marking this topic as [Solved]. See How to mark a topic as [Solved] for a short how-to.
Thanks!

[kingrun]

I don't have the pencil icon shown as described in the how-to. I can only edit my last comment it seems. So I will just mark the solution.