How to complete web events by your own
Step 1: Create 3-5(some events gives rewards for upto 5 new invite) Gmail or email or hoyoverse account, whichever feels the least effortful
Step 2: Create a game uid by Loging in with them in the same server as your main account, as i have seen you just need to login in the game, don't even have to play the tutorial or even go through the starting door
Step 3: Go to the webevent and log in using your new accounts, then copy paste and link your mains code. Sometimes it doesn't work, so what I do is copy the share link from my main and open it in the browser and then login using he new accounts, which automatically links the accounts
Step 4: login in the game from the new accounts
Step 5: Repeat step 3 and 4. As the criteria for returning player in genshin is 14-35ish days of absense so you can abuse this every patch as long as you don't login with the new accounts before linking them or within 14-35 days of another webevent
All of the steps could be optimized to be more easier, I just do this and it works just fine for me
ALSO YOU DON'T NEED TO KEEP CREATING NEW ACCOUNTS EVERY PATCH. YOU CAN REUSE THE SAME ONES FOR AS LONG AS YOU WANT