With your seed words. You can recover the wallet in Electrum for example. In the moment your start recovering, it will close the trampoline channels you had in Phoenix app and funds will be in your onchain addresses. Something like LND is doing with SCB file (LN channels static backups). But I do not think Phoenix/ACINQ will disappear....

Anyways, I would recommend to use the 3 levels stash for your BTC: 1 - HODL = most of your BTC (higher amount) in a cold wallet, will be your "central bank" 2 - CACHE = medium amount of BTC, in desktop, node wallets, will be your "commercial bank", where you do mostly the coin control and redistribution 3 - SPEND = small amounts of BTC, in mobile wallets as Phoenix, enough for your daily spending, will be your "cash pockets".

As I described in this guide "Be your own ban - think like a bank"