They still have models with SD card slots, but they're never coming back to flagships because:
1. so they can milk you on cloud storage or on the expensive variants with more storage
2. access speed difference of UFS 4.0 vs fast SD cards is huge and unacceptable on a flagship that's supposed to compete with iPhones on speed
3. biggest and most important reason I learned from the horses mouth, people used to put the cheapest junkiest "value" SD cards off Amazon in them, which would be slow and negatively impact UX, and would also spontaneously die, taking the customers photos with them, so then the angry customers would blame the phone for both issues("your damn phone ate my photos/sd-card!"), so they had remove it to ensure UX and reliability across the board