I recently encountered a Wiccan who has a devotional relationship with some Hellenic deities and she shared with me that she is regularly told by those on the reconstructionist side that she is not worshipping Them correctly. As someone who has a foot in both worlds, this sticks in my craw. My understanding from working with the Hellenic Theoi over decades within the context of this incarnation is that Their goal is to be back in relationship with us in powerful ways. So I strongly believe that those who are creating uncertainty and hesitation amongst those They have called are working against Their divine will. I'm not sure, specifically, who I am addressing...but I've seen enough of this often enough to know it is a problem. If you recognize yourself in this description, stop it!
What is the point of religion? It is to build and maintain relationships with the unseen, especially the gods. All of the other stuff is means to that end. Now, I am a huge, huge, huge proponent of doing the research, learning as much as one can, and judiciously using what has been learned. Many of the old forms work well (and work in adaption) because they have thought forms behind them that, through centuries of repetitive use, act as a signal and calling card to particular Great Ones. It is fabulous when you can harness that. It is also not necessary.
Similarly, I always say that it is essential to get to know the Great Ones you are intending to work with and to have a thorough understanding of who and what They are and what They want. This helps you deepen the connection and provides a behavioral understanding for you about how to interact with Them. But They are BIG. They are much bigger than us. They can adapt to our behavior and forgive us our confusion.
As far as I am concerned, if one of the Great Ones has called you, and it is not a one-time kind of thing, but clearly one of Them is reaching out to be in relationship with you, it is a really good idea for you to go do the research and be sure that you want to say "yes" before you agree to Their work. No harm, no foul if you want to say no. You are a Divine being living in a body and have free will. So, get a clear understanding. I'm also going to say that there is some wisdom in only accepting life-work from one or two at the most. You really can't serve as a priest/ess of more than that and do a good job of it....although you can do particular acts for some of the others. That's a limitation based on our energy and time. But if you really have been called and you decide to say "yes" then don't let anyone tell you otherwise.
All of the other stuff is means, not ends. It is good to learn it. If you have taken up that kind of work, you should learn as much as you can...but it is better to learn it judiciously rather than uncritically. After all, cultures shift and change. Our written records for ancient Hellenic religion run from about 800 BCE to 500 CE - that is a long time and any living culture shifts and changes.
I have said many times in various contexts that if you call to the Great Ones and They answer - whatever form you use - you are doing it right. If you call the Great Ones and They do not answer, it doesn't matter how ritually perfect or historically accurate your form, you are not doing it right.
I consider what I am doing to be rebirthing rather than reconstruction, specifically because I am not even trying to carefully reconstruct historically accurate forms. I learn everything that I can and take inspiration and modify ancient forms and bring them into rituals because doing so taps old energy currents and helps...but if I am doing my own inner and devotional work (and I am) then They come even without that.
I use the lore to get a really good understanding of what these Great Ones want...of what their agendas are. I use that to inform how I interact with Them. For example, I know the old sacrifices to Poseidon, but I'm not going to do meat sacrifices. I don't raise animals and it would be inappropriate for me to do so in my current circumstances. I can walk to a grocery store and buy meat vs. carefully raising an animal and then going through the slaughter and giving up most of the meat on that animal to the community. As a sacrifice, it doesn't have the same meaning it would in a different context. But what I know, what I absolutely KNOW, is that Poseidon cares for the seas. So my sacrifice for Poseidon is that whenever I see plastic lying on the ground, knowing that without my intervention it will go into a gutter and end up polluting the ocean, I pick it up and throw it away and tell Poseidon, while I am doing it, that it is in honor of Him. THAT gets His attention. That helps me build relationship with Him. I am both doing something in alignment with His agenda, in service of what He cares about, and I am calling Him to mind over and over and over again, strengthening His form and His power as an intercessor for the health of the seas. Obviously, you will never find any reference in the lore to picking up plastic trash, but it works and is important.
This, to me, is the difference. I do believe in the power of research. I believe it is essential to understand as much as you can about the Great Ones you are working with. I think there is a tremendous amount of power to help your magick and worship if you can use references back to old thought forms and tap those lines of repeated activity and pull them into your work. But in the end, it is about the gods. It is about our relationships with the gods. And that means that it has to be about now and our current context. They want to be in relationship with us and it is an act of impiety to inhibit or discourage that relationship from one who has been called to Them. We should be empowering each other to build these relationships, even if those relationships look different than ours. That is the work that all of us are called to perform.