Hey @colonors thank you for your question and your observations.

In terms of investment the first things I would do in your position is to start collecting some summoners: Kelya (water) and Thaddius (death) both of them are sitting at 3$. Slowly you should be able to make them lvl 3-4 all the monster from common rare of these splinter can be rented for few Dec and you should be able to reach Silver 2-1 with a good water deck. Try to make a good excel and stay in the rent price.

Look for a guild, find somehelp for some ppl 75k power is nothing at end of season.

In terms of any element stronger... I would say nah. Every splinter is different with different rules. To some extent Yodin is strong, like Kitty is or even Chanseus. It all depends on rules and comps! I easily beat all Yodin players. So easy lul xd