It depends on which lounge are you going.
Usually entry level card doesn't offer lounge access.
Nearest I think is HSBC which requires 72k annual income.
If you have enough savings, enroll for a priority banking card.
Else, pledge FD for MBB VI.
Google "Ambank Signature Priority Banking Word Mastercard"
Scroll down and look for "Airport Lounge Access", read the T&C and participating lounges.
Generally, you must have a ticket to enter the lounge, once per day (although you entitled for unlimited access).
Unfortunately, Ambank has downgraded the privileges in August and I think none of the domestic lounges accepting it.
Just saw your post after replying him.
Agree that it is useless for domestic lounge.
Nevertheless I am still hesitating to terminate it for the following reasons:
1. Sub-card holder is ELIGIBLE for entering PPL (not many cards allow this nowadays)
2. Still offer quite a lot overseas lounges (of course can't compare with Priority Pass / Loungekey)
3. Unlimited access for Priority banking (anyway, I will opt for other bank instead if go for priority)

how was your MBB credit card application by pledge FD? can share your experience like which branch and how long it take?