> So, how do I create a shared photo album with my friends where we can all upload pictures from our latest trip?

Who is doing this anyway? Nowadays everyone has his instagram profile on private and if you need to share some pics, you do it via Airdrop. lol

There's Immich https://immich.app/ and https://ente.io/ which are both E2E encrypted and not locked to any ecosystem (besides, e.g. Apple only has E2E encryption when you have Advanced Data Protection enabled, and even then not on shared albums). So those apps are strictly an improvement (and I use them). I also do not have Facebook/Instagram/whatever else people are using that don't care about their own or related people's privacy.