Set the battery usage of your essential apps to Unrestricted and your persistence problem is solved. Android has vastly improved its security by cutting off the workarounds shady (and legit) apps have used to persist. Some of these improvement are from GrapheneOS devs hardening the AOSP pipeline and increasing everyone’s privacy. You mention VPN apps getting neutered. I’ve never experienced Wireguard getting killed by Android and I use that app nearly continuously. I also use Syncthing all day. Setting its battery use to unrestricted keeps it working just fine. I use the app’s internal options to disable syncing when my battery tapers off. The hacky workarounds you speak of to maintain persistence on A14 should be killed off to improve everyone’s privacy.