Academic Biblical Studies

I gather from what you said that you are enjoying studying Sacred Scripture and theology through Verbum, and you want more. You're right that it's a bit difficult to know what to recommend to you without knowing your goals and situation. Learning a whole lot of things is good, but I expect you have deeper goals and are inspired by particular topics. Perhaps you don't wish to specify them here (that's ok), or perhaps you wish to be equally good at each general aspect of theology.

Like you, and I think most of us, I have very limited funds, and many interests. I'm reminded of good advice that is commonly given to students going to a university or even choosing a university (esp. for graduate research): it is more important to study a few particular subjects under two or three excellent teachers (wise, knowledgeable, clear, attentive, etc.) than to study many subjects from many only somewhat knowledgeable or somewhat wise (etc.) teachers. The resources of Verbum/Logos are like many diverse teachers - they are definitely of varying quality and usefulness. Some are the best; many are not.

Though I long wanted what was best in Logos/Verbum, it took me years to buy a base package because of how much money I would have to spend on a lot of not-as-great stuff in proportion to the great stuff. In particular, I really didn't want to have to spend a significant percentage of hundreds of dollars on old texts that I could get in the public domain, even though Logos versions were more usable and "enhanced by amazing functionality." (I am very grateful that I finally noticed a significant sale to help minimize how much I spent on the latter, and then found more wonderful sales on particularly great products. I am very grateful for Logos/Verbum sales reps who helped me out when needed too.)

So going for particular academic resources will enable you to go for the best, but sometimes the larger packages, such as Platinum, if they go on a significant enough sale, can be a more cost effective means to get the best, along with a bunch of other stuff that's not the best but is sometimes useful. The stuff you don't use would, I suppose, slow down your indexing and slow down a number of operations insofar as they (many of them) get incorporated in processes that occur when you click on a new verse or a new word in a verse of Scripture.

It appears to me that upgrading to Verbum Platinum from Gold would give you, most notably, the NA28 with manuscript differences and Metzger's commentary, and the BDAG, which are considered the best you can get. It also comes with a good Septuagint lexicon, small smatterings of Early Church writings, Aquinas, liturgy, papal and pontifical council writings, history, Vulgate translation, and dialogues by Peter Kreeft. Those are certainly good to have, but are not considered to be among the most important writings of those authors/categories. For commentaries, I think about half the OT has a reportedly very interesting coverage, and half the NT books have commentaries that would be useful but require some sifting. There's a Protestant commentary set from the 1800s, and some ancient Judaic material. Plus bits of a few other things. Some of these things are probably available in some form or other in the public domain, but not in as usable a form as in Verbum.

What is God calling each of us to do? What do our family, friends, and world need of each of us? Which books out there, in Verbum/Logos, in print, Kindle, etc., will help us best to do what God wants? It will be different for each of us. I suppose as we save and spend money, we need to watch as sales on the books that can be trusted to impart purely and clearly the deepest wisdom and most exact relevant knowledge come and go at Verbum and elsewhere. Some things are so good, or someone might need us to have certain things for them so urgently, that we might not always wait for sales. For what it's worth, those things make up my recommendation.