I'm trying to find an accurate order (not necessarily chronological) to read the Arthurian Legend (I'm complete new to this), what would you recommend?
Just save yourself some time and listen to the original Broadway cast recording of Spamalot.
Read something else and save this for bathroom/beach reading
Sir Gawain and the Green Knight -> Le Morte D'Arthur -> De Troye's Arthurian Romances.
I also liked the Once and Future King, a smart YA retelling of Le Morte, the 15th or 16th century British novel that makes up the bulk of Arthurian legend around today. It was started in 1939 and finished in the 50s. It's quite good, but the last book went out the window a bit.
Start with History of the Kings of England by Geoffrey of Monmouth. Next up read Tristan and Iseult followed the Marie de France's lais Chevrefoil and Lanval. Next up is the Lancelot-Grail cycle. Also consider Erec and Enide if you really want to. You now have the basics.
Now comes character collections.
If you want more Lancelot, the chaddiest knight, read Knight of the Cart by Chretien de Troye
If you want Gawain, the objectively best knight, go for Sir Gawain and the Green Knight and The Marriage of Sir Gawain. Both are great.
For more Merlin you'll want The Prose Merlin, and Mary Stewart's Merlin series isn't bad.
To see some badass Arthur read Culwich and Olwen.
Saga of the Mantle is great for a laugh if you want to see the Round Table get mega cucked
Once you've read all of those read Malory's Morte D'Arthur to see all the stories brought together into one world. Sorry in advance if you're a Gawain fan, Malory hates his guts
For good modern stuff you have Once and Future King, Connecticut Yankee in King Arthur's Court, Mary Stewart's series as mentioned, and Mists of Avalon if that's your thing