SFO-HKG is a 14+ hour flight. I would not even consider PE. And anyone who's choosing UA for the food is in for a big disappointment.

We do SFO/LAX-BKK several times a year. CX would be my first choice but its fares are consistently running at least a grand higher. We were consistently flying SQ, and also tried NH recently. SQ's service and food have become pretty inconsistent (check the SQ forum) and I felt NH soft product has also declined post-covid. Bottom line is I was surprised to find that UA is now competitive on these routes so long as you adjust your expectations on food (noting that I've gotten really disappointing meals on SQ, NH, BA, and EY within the past year).