... but I'd say we're probably not seeing any new Eld updates for at least a year or two
A year or 2 is probably how much it will take to complete the first Arc, then the compiled version depending on the scope will take (probably) another or more, since earlier chapters will suffer many changes when they get remade in Unity, for example just the first chapter will (probably) have the entire castle map remade and expanded, maids will also (probably) have their designs reworked and there's even the possibility of new content being added to it and to the other chapters.
Only then Eld development may (or not) resume, and before intro even begins working on new content, the game will (probably) suffer a rework to improve on certain things that intro wasn't satisfied with. Only thing that is completely done is the main storyboard.
Quote when someone asked if there was any lore behind the gravestone found in the main hub of the game: "None that you know of... To be more specific, since the story and lore for Eld are basically complete from start to finish, I do know exactly what the lore is. The question is whether I'll ever get around to fleshing out that lore in future updates".
Intro doesn't really have timelines. He can't even predict the release date for the current project that is being worked on (ch. 8) and only gives one when he is absolutely sure the game is really (that is usually after the Alpha test phase is concluded and all major game breaking issues are fixed), and what comes after will depend on what he is more inclined to at that moment.