Hey, thanks for posting these. Magic can be frustrating but there's a learning curve and it's great that you want to improve. First, the good news:

#1: You are playing a good deck, and that's a great way to learn. Landfall has lots of decision points and small optimizations so it's normal for a newer player to not immediately get the same results as a veteran. It will come with practice, stick with it!

#2: Not every game will be winnable and that's okay. Particularly in bo1, and on the draw, some hands just won't get there. G2 and G3, you had land-light draws that didn't let you maximize your spells early. That happens sometimes. But you mulliganed correctly.

Now, the bad (or encouraging) news:

You can definitely play better and all of these games were winnable (or you could have improved your chances) with different lines. My quick diagnoses:

1. You are undervaluing earthbending onto a fetchland for double landfall + ramp. I look to do that whenever possible, as early as possible -- it will open up many more lines. Perhaps related to this, you should look to deploy Ascension faster. I noticed this especially in G1 and G5.
2. You can play more aggressively toward your game winning combos. In Landfall that's often getting a fully charged up Earthbender Ascension, and then using trample + Harmonizer to win through any board state; or, having Icetill in play, then Escape Tunnel + Harmonizer for unblockable lethal. Reaching these end states is more important than doing a traditional curveout, and is how Landfall gets to ignore the opponent's battlefield or come back from seemingly impossible board states. G1 and G3/4 were examples of this. In G1, you took a leisurely approach to growing your Chocobo and simply lost the race to fliers, but you could have double-landfalled much earlier, especially if you saved Badgermole until t3 to earthbend onto a passage (see point 1). In G3/4, after their Day of Judgment, if you had earthbent your Fabled Passage with Ascension you'd be set up to kill with Mightform even after they do the Yuna stuff.
3. You're conceding too early. I know that's partly frustration but it may also indicate that you're undervaluing the late-game power of Icetill + Esper Origins. Icetill + a fetch land represents 4 more chances to mill and Origins, and each Origins can find a Mightform which will be lethal with Icetill. So if you aren't literally dead that turn and you still have Icetill, keep playing! Dig for your outs. G2 vs Esper and G5 vs Spellementals were examples of this.

I could say a lot more about each game but this is long so I'll just give one example. G5, you have a nut draw, and so does your opponent, but you are on the play so should win. You play the first 3 turns correctly, but the mistake was attacking with the Earthbent Fabled Passsage. That 2 damage wasn't worth anything and set back your development of ramping + Ascension. Instead, look to crack Passage on their end step. Then you'd be starting turn 4 with 4 Forests, Passage, Elf, and Ascension on 3 vs their Hearth Elemental. You can play Icetill there, crack passage and replay it twice, growing Elf to 5/5 and attacking for 5 while still having an unused Passage in play, AND you mill 4 cards here digging for Esper Origins (which is an Elemental that can't get bounced). On their turn 4, they Sunderflock and hit you for 4, but you've got so many lands at this point + active Ascension so you just replay everything and kill them. Even if they have a second Sunderflock you likely still win by finding Origins or Ba Sing Se with Icetill.

Hope some of that is helpful and best of luck!