I usually put all the relevant travel data in my Joplin notebook.
If the tickets are availible as .passkey files I manage them with PassAndroid.
Transportr for public transportation.
Wireguard if you need to access your home network via VPN.
Thanks I just tried PassAndroid, pretty slick! I was using KDE Itinerary (way more features and always improving, but not too polished yet) to manage tickets before, now I have an alternative.
Regarding wireguard I always used WG Tunnel from f-droid, I'm looking at the official Wireguard app screenshots and it seems to have the same functionality (easy config import via QR scan, notification shade button), maybe it looks prettier. Not on f-droid, that's why I didn't come across it before.