@spud1 ,
If you're up for creating your own, check out a product called
Notion.
I'll try and sum it up... at the most basic level, it's a digital notebook that allow collaboration. But pages in the book don't just have to be text and images, they can be databases where you can define the various fields. It's very easy to then create relationships between databases... so PRODUCTS can be referenced by QUOTE ITEMS for example, which are in turn referenced by QUOTES.
It has good task management facilities as workflow/task management is one of the reasons a lot of companies use it. It's available as a desktop app for Windows and Mac and it's available as a mobile app for Android and iOS. The last time I tried off-line working, it did have a limited ability to work off-line in that it allowed me to edit the items I had recently worked on and that were cached locally... the changes I made did indeed find their way back on-line when I did get an internet connection.
The other side of it is, there are people out there selling templates which are effectively self contained sections of notebook that provide various bits of functionality. Some are free and some are commercial. If you do take a look and need help, I may be able to assist as I'm working quite a lot with it at the moment as I use it to keep all the information I had floating around in my head straight and in one place. There's also lots of videos on YouTube about it, and just getting some free templates and looking at how they do stuff can be enlightening.
Whilst it may not be the final answer, what I'm finding as I'm using it is that it can serve as a nice prototyping approach, to flesh out what you want and how you want things to link together and work. To give you some idea of what one section of my workspace contains....
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Some of these (Guidance, Technical Notes and Common Blocks) are actually pages that contain useful information... the rest are databases. The bulk of the complexity is in the project management side, the rest are mainly simple lists of different bits and pieces. Projects for example support sub-items, so you break a big project up into a number of smaller projects each with their own tasks (which also support sub-items to allow you to break them up).
As I say, the web is awash with information about the product, loads of info, loads of tutorials and loads of templates to get you started.