For storage: Any trustworthy hardware wallet like Trezor or Bitbox. Don't hold coins for a long time on any custodial or hot wallet as that heavily impacts your security.
For buying or selling: That depends on your needs. There are Bitcoin only providers in Switzerland for example like pocketbitcoin or relai which have a very good reputation. For other coins you can go to one of the famous big platforms such as binance.
If you want/need to buy without KYC process, check out https://kycnot.me, but be aware that this will complicate things down the line when you want to sell your coins as many vendors need you to prove to them how you bought your coins and from where.
In the EU there is a regulation that from 2025 onwards vendors will have to identify you (research MICA for details). Only P2P platforms will remain untouched by then.