Hello,
Sorry to hear you are having issues. If you review Fences history here: https://www.stardock.com/products/fences/history. Fences 4 was out in late 2021. And Fences 5 was release late 2023. Hence Fences 4 has been around 2-3 years. As for, will Fences 5 be upgrade to Fences 6 and the need to upgrade to it, that all depend on how Windows 12 changes.
Lots of user still running Fences 4 on current Windows 11 version without issue. For your issue on Fences 4, you can always do 30 days trial on Fences 5 and see if the new layout engine available in Fences v5.54 and later help on your issue, then you can decide if it worth for your upgrade.
Thank you.
Basj,
Stardock Community Assistant.