Your considerations are spot-on. Very nice question.
You should definitely be familiar with your genre. If you know enough to place your work within a specific genre, then it had better fit there well. Each genre has its own rules, guidelines, conventions, expectations, cliches, and fatal faux pas. Writing with little personal familiarity with the genre is very likely to be blundering around; even if you write a good book, it's very unlikely to be a good genre book.
On the other hand, you do not need to be an academic expert, and furthermore you do not need to be up to date with the cutting edge.
You don't need to be an expert because most of your readers won't be, and won't care about the academia - they'll care about the story. To take an example from my own home territory of SF/F, you don't need to be able to pinpoint precisely whether your story is a "proper" science-fiction piece and whether it has literary merit, or whether it should be categorized as "magic realism" or more "slipstream". You can, but you don't need to in order to write, nor in order to be read.
Nor do you need to be extremely up-to-date on your genre, aware of all the latest stories and authors and ideas. Partially because, again, a lot of your readers won't be, so they won't care. Partially because it's safe to assume that anything that's your own unique idea will be distinct enough from other things going on that it will have merit on its own. You should be aware of huge things, works that are massively popular (or notorious) - I can tell you that urban paranormal is different after Twilight, even though I've never read the books and I'm not a fan of the genre. When there's something big and current, you should be aware of that, and figure out if it affects your own work - it might; it might not. The Matrix didn't affect time-travel stories much, The Time Traveller's Wife did. But huge changes like that are pretty rare, and fairly easy to keep up with (particularly because you don't have to actually read even the genre-changing ones unless they directly pertain to your own specific work).
So, you should be familiar with your genre - to the extent that you could read a genre book, and express an opinion on whether or not it was a good genre book. That's the same judgment you'll be using to examine your own work. But you don't need to be constantly reading in your genre - it just doesn't change that fast. And if you personally find that reading in genre can cause problems for you, like the ones you detailed in your question, then IMHO you're quite right that it isn't necessary and can be avoided, if so you choose.
I'd consider reading in-genre very occasionally, just to "keep in touch," as it were. From your description, I don't think that would cause the problems you're concerned about, and I think it would be beneficial. But as long as you remain a good judge of how your writing will work within your chosen genre, anything else is entirely a question of what you like and what works well for you.