I've posted about this just a couple months ago from this one folks need to do better searching on these forums to save themselves a lot of time. With that said I'm surprised you all are wasting time splitting json files when all it takes is restoring (after identifying since their docs are incorrect) the SINGLE sqlite database file to restore (with Chrome closed) - assuming you have file-level (or shadow copy) backups running. If done properly, ALL SB DATA is restored, sessions, settings, etc. in the matter of a few seconds. If, however, you do not have any system/drive level backups but for some reason cared only about SB session backups and have that - then yes, because of how they coded the loading loop it flat out exhausts available resources and crashes if the backup file is larger than approx. 40mb and will never succeed as you all have found unless a hacky method of file-splitting is employed. Again it takes mere seconds to fully backup/restore 100% of all SB data and settings if you are backing up your Chrome "user data" profile folder.
Should their own backup/restore in the app work? Hell yes. I along with probably a few zillion of their users have either posted here or directly contacted them and received replies basically finger-pointing at the Chrome browser architecture as the reason why their own code not only does not work, but does NOT more importantly have error handling written to handle the crash - and as a DEV myself you CANNOT blame Chromium for your extension crashing without even telling the operator why the error occurred and at what point in the code which is just basic coding 101. Their responses I have seen have never indicated they even cared that it was occurring to everyone, let alone indicated any planned action they were taking to even improve the error handling (assuming they cannot simply code the loop to read in CHUNKS at a time as users have now been forced to do manually). Hence, I'll personally keep using it but just ensure I am taking regular offline profile backups of the SB database so I simply bypass their broken routines all together.
As for general Sessionbuddy DEV efforts though I seriously now hesitate to contribute any more $ to this product effort since even their basic blog hasn't had a single update in well over a YEAR, their "DEV road map" has also not been updated in 18+ months and even then, conveniently contains NOT A SINGLE DATE, either past or forecasted making it the equivalent of "yea we're working on stuff....don't ask us when" yet they continue to ask for DEV dollars and claimed they would be transparent in their efforts (and leave up posts indicating there actually ARE some active efforts. Does anyone outside of their own DEVs have any firsthand knowledge whatsoever as to what those efforts are? Have they have even written a single line of code on this product over the course of EIGHTEEN months that not a single update on ANYTHING has been posted?!? (Whether to even just patch existing version issues let along towards the new major release codebase)
I mean, I've been wating YEARS for a simple 2-3 color dark CSS theme to stop being blinded at night anytime I use SB. You'd think 2 full YEARS into the "v4 roadmap" perhaps even just a tiny feature like CSS dark could have been released into the current codebase just to give their users a tiny taste of things to come, and so we know they are still alive. :)