I know a blockchain wallet is a safe way to store, manage, and spend your cryptocurrency. I know all about the types of wallets ranging from Cold storage to hardware. Recently I decided to use a VPN when carrying out a transaction. I know I am not that techy but I have got to ask, is there / will there be a security issue when handling such transactions?
Using a VPN will not effect the safety of your coins, unless the VPN itself is unsafe. You'd have to be using a pretty obscure VPN for that to be the case though.
I would recommend focusing on your system security. If you are not entirely sure if a VPN will effect your security or not, then this does raise concerns about whether or not your system is safe, or if things that seem safe (like system "cleaners" or "anti viruses") that actually aren't are existent.
If you're using Windows, please be safe. It is generally an unsafe operating system and it is most-targeted by attackers. Look into Linux and getting to know this OS if you aren't already.
Paper storage, encrypted external storage or cold wallets are your safest bet for wallet solutions. Only keep a minimal amount of "spending" coins on a wallet that connects to the internet from your computer, especially if it does turn out that you're using Windows.
Stay safe!