It is possible to get to the top after take a break.
I know because I've done it recently. There are counters to the current top teams that hold reasonably well in arena. (I drop into the 40s or 50s most days but can usually climb with only spending 50 crystals on refreshes. Though some days I spend 150 due to bad rng). But I can usually get 1st or at least top 5.
I took an 8 mo break starting in October when the Malak fisico happened. At the time I had a Darth revan team with a six star malak and regularly got 1st. After only a month of being back, I can beat Rey teams (even the ones with jedi luke) and there are enough of those to climb. Though I also have to beat gas if I fall too far.
The team I use for Rey is Vader, Darth revan, badstila, thrawn, and a 4 star 10th wat. It works and it doesn't really require to many characters that you couldn't have by now. Though it depends on how long your break is for.
Wat is pretty much required but doesn't need to be high gear as if modes right you'll get use of him before the other team really takes any turns. Darth revan is helpful because he fears everyone but Rey and jedi Luke if they have him. Vader stacks the debuffs, badstilla adds even more and you saber throw rey to death and clean up.
To get through gas teams, I use Dr, badstilla, hk, malak, and raid han. It's pretty consistent for me but not as much as my vader vs Rey. So some rng required. There are other gas counters too but this one doesn't require me to move mods.
So yes it is possible, you just have to work at it.
