https://youtu.be/KUCjI-lVHyE?si=bqh-NzovvTejxWV-

Basic level info. Basically you don't want small chunks of bitcoin. Fwiw I try to keep my cold storage utxo greater than 1M sats.

As for coin control for managing your utxo, I have used Blue Wallet https://bluewallet.io/ it lets you see your various "chunks" of bitcoin and manage them. I haven't set it up, but Sparrow https://sparrowwallet.com/ seems to be a good choice for desktop. It is also possible to just sweep a wallet, combining all of its utxo to one, with most wallets.