I didn't participated in the Hues of the Violet Evergarden Event and I noticed that players can get Xingqui for free if you meet and finished the event requirements (Itadori Festival). I didn't know about that because I'm too busy exploring, is there a way to get Xingqui again aside from Banners? I searched the internet and I never found any blogs about it if I can still get Xingqui this late.
Outside of specific events like this recent one, Xingqui isn't part of the few characters you can get for free.
Outside of banner pulls, your only chance is to wait for another event where they would give him, or if he is one of the two 4* characters in the monthly rotation in the store for Masterless Starglitter.