The vast majority of us will never encounter such a scenario but...
Outside of asking a family member/friend to retrieve your HW wallet and/or seed
What do you do in such a scenario?
While it's generally not recommended, IMO this one of scenario where brainwallet or having encrypted cloud backup may help you.
Yes I have read that brain wallets are not 100% reliable, it still might be a
good idea to have a second HW with some coins and make it an exercise to
memorise the seed. Everyone should do that while still having the actual seed
secured elsewhere.