Taking the low cost carrier seems to be a no-brainer. But the connection time is short.

Can you book a longer connection? Or take TG only for the BKK-HKT flight? Or consider flying the next day?

The BKK-HKT flghts are full at the moment, so missing a connection without a back-up plan is not a good idea. You may want to reserve a 2nd, later flight, unticketed. TG, PG both sell changeable tickets. Nok Air does too, but they only fly limited dates to HKT until Nov.

I'd still go for the lowcost carriers.