I do love the little menu, it's brilliant! I do have a problem with it being stuck on the first page - or how you would call it - though. If I install the ProductivityResearchForEveryone mod, it will populate normal tech menu with all the tech - but in this mod, it gets locked agfter Solid Fuel from Light Oil. I assume new techs are there, just not accessible because there is no page switch or slider? I do play at increased UI size.

There should be a slider on the right side if there is too many items.

Might be an issue with the increased UI then. I can look it up later.

With a bit of testing I can confirm there is a slider when more tech is researched - nuclear in my case. The problem seems to be more so very strange way the new productivity technologies are created. Migrating from the original "productivity for all" mod to this one removed over 2 dozen (!) techs, notably solid fuel from heavy oil and petroleum, while keeping the solid fuel from light oil one.

One reason why there is way less techs is, that recipes with the same output get grouped together into one tech.

I actually just noticed that the Technology Name states "Solid fuel from light oil" even though it has all variants (Light Oil, Heavy Oil, Petroleum, Ammonia)
You can actually see that upon putting it into research and look at what it does.

But the original issue really seems to be a GUI Scale Problem.
What Resolution and Scale do you play on?

I see - lack of separate technologies that exist in the pre-fork version is what threw me off. Later in the game with extra tech I can see the menu scrolling normally, and checking in the technology screen "solid fuel from light oil" does affect all the recipes correctly. In the end, communication problem more than menu problem.