Returning player

Hey all, I'm looking for help/input on how to proceed onward. I have been playing on and off for I think 4-5 years maybe, and I have never had fixed goal or strategy, just went with the flow I guess as F2P player (haven't seen any sense in buying 20+ eur pack to get 5 shards) . And I just started playing again more a bit over month ago, and seeing all those OP teams out there and new toons coming out so fast I was wondering if anyone could point me to right path on what to focus or where to go on?

https://swgoh.gg/p/887113494/

Any help from you experts is very much appreciated :)