All coins are from kyc exchange and have been in cold storage a while.
So, given that your coins were bought via a KYCed account on a centralized exchange, then it is safe to assume the exchange knows exactly how many coins you own, in which addresses you are storing them, and has linked all that information to your real name, address, and other personal information. By extension, all of this will have been shared with various blockchain analysis companies, most likely some branch of your government, and potentially a variety of third party data brokers or other interested parties who buy data from blockchain analysis companies.
So now you have to ask yourself how happy you are with all of this. Do you not care that all these entities know exactly how much bitcoin you own, exactly which addresses belong to you, will be able to track exactly any future movements, transactions, purchases, trades, etc., that you make, and potentially use this information against you in some way? If you don't care, then do nothing. If you do care, then continue reading.
Next ask yourself what coinjoining will achieve in this case. Let's say you split all your coins between multiple coinjoins, coinjoin everything thoroughly, and move all your coins back to a brand new wallet with no links to your previous addresses. This will prevent the entities above from knowing which addresses you are storing your coins on and from being able to track all your future transactions. They will still know that you own some bitcoin, but will also lose the ability to know exactly how much. Their estimates of how much you own will become less accurate as time goes on, as they won't know if you are spending or selling some of your stack.
If you continue to buy bitcoin via this KYCed account and then coinjoining it, then again they will not know where your coins are or what you do with them, but will still have the data on how much bitcoin you bought over time. If you instead choose to buy non-KYCed coins via a DEX, then they will not have this data,
provided you are meticulous in keeping any non-coinjoined coins separate from your newly bought non-KYCed coins.
And of course, make sure you don't use Wasabi to do any of this, since they work hand in hand with blockchain analysis companies.