imo , when you weigh up the cost of travelling back and forth effectively 4 trips , I don’t know where you are , but for me personally cost effective via an agent .. it took 10 min .. and they called me on its return, asked if I wanted it deliver to my address or come into office to collect , which was the option I chose .. 😉👍🏻
About 3 years ago I had to renew mine , agent Pattaya , took 3 weeks 10,000 including price of new passport .. door to door .. saved me travelling and possibly staying over twice in BKK .. pretty good all round imo .
Should be fine .. it’s only if her flight gate is the opposite end of terminal .plus she won’t be the only person transferring I’m sure .and the connections flight will be aware of that