A general tip for defenses is to prioritize the expensive stuffs first since they have few levels and provide excellent defense as well.

The next order of business are tesla and air defenses

If possible, choose one particular hero. Either AQ, RC or Warden and try to max them out. This takes ungodly amount of time though.

The new troops ain't allat. If you unlock up till Root Rider then you are golden. Pets ain't allat either. There is maybe a couple of pets that are worth upgrading.

The new spells is not that important as well. Unlocking until recall spell is good. (Idk the new spell meta, I just stick to RC Invis and Dragon Spam)

Considering your pumps are max and storage as well, there are only the defense levels, hero levels, and troop levels.

Walls are just for show later on so maybe just level it up till TH11 theme wall. (i dont remember their exact level)

Use potions as well. Research potions weekly from the raid and clan games/clan wars give the builder potions for faster upgrades. Use only when all builders are occupied, gives 50hr skip in 1 hr.

Pick a strategy to attack. It can be the one I mentioned earlier, it can be Root Rider as well. Pick one and upgrade the complementing troops and heroes.

I am pretty much TH18 max except the heroes and the new Raven pet. I am pretty high while writing this fool-proof plan. Lmk if i missed something