This may be a hot take but I'd like to speak my peace
I don't ship Frodo and Sam. I really just can't see it.
*Just to be clear, you can ship whoever you want within the realm of reason, I just want to share my confusion on the conclusion a lot of people have gotten to since I can't personally find that perspective*
I haven't read Lotr yet, but so much of this shipping context is derived from the films so I think I'm safe to say that they (the actors and writing) don't at all act with romantic subtext.
Throughout all of the films Frodo and Sam's relationship is very much that of close friends who bond differently during the journey due to dependency on each other and hardships.
Sam is the closest person to Frodo through this intense burden and psychological/moral turmoil. Sam carries our boy to the mountain because he's been with Frodo the entire journey from start to end, and has seen the toll it has taken on him. He carries Frodo with an air of camaraderie, loyalty, care, and emotional strength.
Anyhow, the fact that Sam and Frodo don't exist in a romantic context together is cinematically supported, and I can't find it at all in the way that the actors portrayed them or even in dialogue.
Personally (and you can metaphorically sue me for this if you want) i have one specific friendship of my own that I very much see in Frodo and Sam when I watch The Lord of the rings trilogy, and this is my lifelong friend and platonic soulmate. We tried to see if dating was for us since everyone said we should and it didn't feel right on either side (this was middle school, mind you, and now we're in college).
I see our friendship and our type of platonic love in Frodo and Sam because of the sheer amount of obvious love for one another present without any romantic influence between the two.
And, I also see the crowd calling for queer romance just because of two same gendered friends with a deep bond. To me it looks like people have blatantly ignored a prime example of positive and strong friendship between two men in favor of the ever present gay-ship fandom fodder. It also is concerning as I see women primarily vouching for this ship specifically.
Mind you, I am a queer woman, and I have a multitude of queer ships that I'm a fan of, including mlm (like merthur, which is my personal favorite). I just can't see what others are seeing when it comes down to Sam and Frodo's relationship type.
Frodo loves Sam, and Sam loves Frodo, this much isn't even up for discussion, but it's important to distinguish between the love you share with a friend and the love you feel for a romantic partner.
It's very clear that Sam loves Rosie, as we Begin the trilogy with Sam admiring Rosie from afar and Frodo encouraging him to be a little bit more brave. We end this series with Sam marrying Rosie and Frodo is happy for him. Frodo himself is depressed because of how the journey changed him and his perspective of the life he once had, which is unrelated to the fact that Sam found happiness and he couldn't after the shared journey.
Again this is just an opinion, and also kind of a vent post in a way. I really just don't understand how this conclusion is so popular. People are bound to get to a conclusion of shipping two characters that don't really mix in a fandom, I know that to be very true. It's just strange that this one is so popular, since it's got such little usable context to support the ship with.
I'd love to know what others think tbh