Change addresses are also the reason why deterministic wallets (ie. ones based on a seed) are recommended over non-deterministic ones. With non-deterministic wallets it is recommended to make regular backups of your wallet file whenever you have sent a transaction. I remember Bitcoin Core being one of the wallets that use a non-deterministic address derivation scheme, not sure if that's still the case though.
Correct. This is one of the reasons why Bitcoin mixers entered the market in the first place.
You could also try to jump between alt coins; but this is rather bothersome, may cost you in terms of alt coin volatility and may still be traceable across chains due to the temporal sequence of similar-sized transactions.
Alternatively you could look into privacy focused alt coins such as XMR, which comes with built-in mixing properties, but is currently more volatile than BTC and not as widely accepted, meaning you will likely have to go through an exchange at one point of your transaction. Additionally some privacy focused alts may still be broken at one point in the future.
So in the end mixers are probably the most convenient and safest way to retain your privacy, unless you plan to go long on XMR and have places to spend it at.