Please look at this post:
https://together.bunq.com/d/12958-bunq-travel-card-faqs
Under Travel Card without subscription.
And look at the bunq website:
The last two Points matter:
https://www.bunq.com/pricing/travel-card
Top up with Ideal, Sofort or BANK ACCOUNT
Top up with debit or credit card.
And in the travel card subscription no Bank account is included. So only your Card works.
And you can top up to one bank account but not pay from it.