I had a Fiesta.
Bought in 2017 with 20,000 KM on the clock. Transmission shat itself after 5,000 KM. After going in and out of the Ford dealer 4 times due to their cheapstake trial-and-error fix as they've been advised by the parent company, the transmission was replaced under warranty, taking over a month and no loaner car given (I don't know why I still expect to have this Thailand, but it's quite pathetic to expect customers to use the non-existent public transport in Pattaya).
Reached 50,000 KM before selling it, had no issues after transmission was replaced. But 30,000 KM is absolutely nothing and doesn't tell anything about whether or not the transmission will last. For those who really want a Fiesta, buy it and manual swap it. Costs 50k including labor and 100k in depreciation because it's a manual.
For those that really want a Focus but are worried, get the new one with the 1.5 ecoboost engine, the transmission has been replaced with a traditional torque-converter automatic. 2 year old Focus for 500,000 baht is a steal in my opinion.