I looked over Games 1 and 2 and imo the skill difference between you and Nauz is vast enough that these games are kind of tough to analyze. I'm (pleasantly) surprised.
Here's my cursory analyses. I didn't look at the actual orders within turns so I might've missed some cleverness there:
Game 1Theme: Nauz learned the hard way the trade-off between South America and Oceania and the difference it makes when you are 1 hop to North Africa vs. 2.
Verdict: Decided on picks. After picks, it was sanmu's game to lose.
Let's start with the board:

We've got a SA FTB with East Africa in play, so North Africa might have an 8-stack on turn 2 if you go to the FTB; this is game-ending if you got 2nd pick. We've got an Oceania FTB. NA is 3 turn, Asia is not in play because someone nuked Japan (Truman, is that you?). This leaves Europe (2-turn +5) and Africa (to counter Europe and SA) as the other two viable starts.
Both Nauz and sanmu picked the same 4 places, in almost the same order:


Seeing the 2 starts adjacent to North Africa, both picked Europe 4th. The only difference between the two is that Nauz picked Oceania 1st, while sanmu picked SA first. Some have chalked up Nauz's preference for Oceania up to a newbie error, but I don't think he was that naive. I think he analyzed a few SE games from the ladder but couldn't fully contextualize their rationales:

Anyhow, when your theater of action is Europe and Africa (the center and breadbasket of this map), South America's armies get there fast, without additional effort. Oceania's armies don't.
sanmu's picks made the SA FTB viable: he would get both FTBs, start 1/3 (SA+Africa, so no threat on turn 2), or start 1/4 (first move turn 2, so taking the FTB turn 1 is survivable). If he got 2/3, that's his toughest-case start but even then he has control of North Africa on turn 2 and isn't in a particularly bad spot.
Nauz's picks are shakier, purely because he picked Oceania over South America. With SA, he does take the FTB safely (since he can only get SA on 2/3) but his 1/4, as we see in this game, does not actually counter his 2/3.
So the game starts:

Intel is a wash: Nauz has 1/4, sanmu 2/3 but sanmu only needs to plan for Nauz being in Europe. If Nauz isn't in Europe, sanmu has ample time to react to a North America or Asia gamble.
Nauz is at a disadvantage now. Both take their FTB's on turn 1 but Nauz tries to battle his way in to breaking SA while sanmu just takes North America behind the fog, since Nauz deals with the inefficiencies of playing on offense. By turn 5, the game is sealed- but it wasn't really exciting on turn 1 either. More or less decided on Nauz making the wrong choice between SA & Oceania on picks- Oceania on this board was only viable in conjunction with East Africa imo, and Nauz didn't see that.
Game 2Theme: Nauz learns about the difficulty of holding Europe.
Verdict: 90% decided on picks. I think Nauz just struggles still with reading a Small Earth board.

2-turn SA, 2-turn Oceania, 2-turn Europe, Africa starts in Madagascar, and NA is 3-turn.

This time, we see a much bigger difference in how the players read the board. sanmu sees SA and Europe as the 2 biggest threads on the board and goes for them, with Oceania in play if he has to settle for unsafe Europe. Look at his 1/4- it's a strong counter to his 2/3. sanmu recognizes here that the NA start is only 2 hops from Greenland and so, if his opponent goes for Europe, he makes that bonus absolutely non-viable at the end of turn 3, with a double-border and an additional border.

Nauz reads the board differently. He once again picks Oceania over SA, settles for Europe/SA if he doesn't get Oceania, and then picks a 4 that counters his 2/3 somewhat adequately (North Africa). I think Nauz just didn't read the board quite as well as sanmu again.

Nauz gets his 1/2 while sanmu gets 1/4 and is perfectly in place to counter Nauz.

Both players take the obvious opening moves, with sanmu setting up his Europe counter while Nauz goes for 2-turn Europe + 3-turn Oceania.
Europe is broken on turn 3:

Notice how sanmu plays conservatively in North Africa this turn instead of gambling the whole house on a delayed attack from North Africa to Europe. No, he just has a late-turn 3. If he doesn't break Europe this turn, he lives to fight another day. But he breaks Europe, from Greenland, since Nauz had to defend his bonus at 3 whole points.
After that, sanmu lets SA fall so he can take North America;

Then he fully seals the game.
Imo we're seeing a massive difference here, because sanmu is playing like someone who's played a lot of SE while Nauz's analyses don't seem to be able to keep up quite yet. He just isn't reading the board and understanding the threats and plays the same way sanmu is. Perhaps this is because he's forced to think on a much more micro level than on medium-sized maps.
We'll have to see. But so far these two have been fairly boring games where sanmu made the correct picks and Nauz didn't.
Edited 5/24/2021 06:21:07