I'm not misreading or misinterpreting the rules; I'm stating that the 5e version sucks for players who want to use a lycanthrope as a character idea.
In 3.0/3.5, I could see the excuse of afflicted lycanthropes being cursed. But the ones that inherited the template?
You can't inherit it, at least not in the official rules. It is not a playable species. Barring hombrew, every PC who has it in 5e got infected by another lycntherope and were thereby cursed.
How is that a curse if you were born as a lycanthrope and raised to "not be a monster?" Forcing the player to "be cursed" and to eventually "lose their character" is a thing that a DM doesn't need to do to the player, but the 5e rules pretty much enforce this. I feel like the core post is looking for ways to make it all enjoyable, but most of the replies still appear venture into "Yeah, no. They shouldn't enjoy it."
If you are infected it is curable with remove curse. Unless as a DM you are severely restricting the availability of magic it should be a temporary affliction. If a player chooses not to do that because he likes being immune to non-silvered weapons, that it is a choice and one with pretty severe consequences.
I would argue if you are going to hombrew the game so PCs can be born a Werewolf, you should also hombrew that they can cure it with remove curse and don't need to search around for a Wish. That would make it very playable and if you are starting at level 1 searching for a cure could be a main quest point because remove curse is not necessarily widely available at level 1, but by level 5 you should definitely be able to get your hands on it.
I feel like the core post is looking for ways to make it all enjoyable, but most of the replies still appear venture into "Yeah, no. They shouldn't enjoy it."
The core poster said specifically the PC was infected, not born with it. He asked how to let a character embrace it and at the same time not completely wreck game balance.
Being a Lycanthrope is extremely powerful in combat, especially at low levels. The way to
balance this is to impose severe penalties in accordance with RAW. That is how the curse works and it is how you provide a counterbalance to the huge combat boon. It really is that simple, is relatively easy to do and relatively easy to balance. But if you don't want to impose the negatives of the curse at your table and only give the massive positives, then the game is not going to be balanced without the DM resorting to some cheesy metagaming.
I am not speaking from a whiteroom or theory perspective here, I am speaking from experience. As I noted above, I actually played most of POTA with a Wearboar PC in the party (not me, another PC). He became infected early in the game in Rivergard Keep. The campaign was fun for all of us. The DM did about half of the things I mentioned above, and would have done some of the other ones he didn't do if it came up.
In our game the character was clearly cursed, there were positive consequences and some severe negative consequences and those served to counterbalance each other but we did enjoy the game. It probably helped that we were a Nuetral/Evil party affiliated with the Zhentarim and as a party were primarily in it for the profit. We were defending civilization from the elemental cults, but for the good of our coinpurse, not the good of the citizenry. If we were a good aligned "knight in shining armor" type party it would have been a lot more difficult I think and probably the other party members would have forcibly removed the curse (as I mentioned above I came close to doing that anyway even in our evilish party).
If you are not going to impose the penalties associated with the curse, then the only other option to achieve balance is to homebrew the effects of the curse itself and eliminate or tone down the positives. If you do that though, not as many players are going to be excited about embracing it.