Unconfirmed btc transactions never get stuck for 20years. There is a limit period of 14days (according to bitcoin core), after that your unconfirmed tx will return back to the sender's wallet.
That's true. However, there is a but. You might be using a software that will rebroadcast your transaction over and over again. For example, every X days. If that is the case, and your transaction got rebroadcasted to the network, the nodes that already purged it from their memory pools will again receive fresh information about it. As a result, they add it to the mempool again. The counter (those 14 days you mentioned) starts all over again. Instead of 14 days, you now wait 28 days, etc. I think that no node on the network can have your unconfirmed transaction in its mempool for you to get the coins "back". If one has it, it's going to share the info with its peers and then those peers will share transaction data further, etc.
