Ok....let's clarify some concepts here.
Having the "money", either crypto or fiat, it's of course the best option and you can run the show on your own if you wish to do so.
However, regardless the name you wanna use, bank, financial institution, payment processor, initial payment processor, gateway....well, the basic requirement it's common to all of 'em: you need a LICENSE!
What differs, it's the amount of "paperwork" (read manuals) and minimium capital requirement you have to satisfy.
The fact you don't wanna look into a brick and mortar bank, it's ok...you'll save a lot of money in infrastructure.
And the fact you wanna, eventually, consider a different type of license, let say the Panama FSC one just as an example, it's ok as well since you'll be investing between 25 and 100K, depending you wanna have the SWIFT access as well.
Therefore, way below the required millions of euro/usd for a traditional institution.
However....this is just the beginning of your proecess and the easiest issue to be solved.
The real problems will arise in the moment you'll be looking around for a "nostro conto" at any given place in the globe for your "crypto bank".
Without one or more correspondent bank, how would you guarantee the payments and the flow of transactions for your customers located in different part of the globe or just in two contiguous countries?
The problem for setting up such type of institution, regardless their magnitude, is always the same....relationships.
Beside the small or big amount of bitcoins/altcoins you're sitting on...do ho have this type of relationships?
If the answer is yes....well, why waiting? Just toss a smal portion of crypto and get the less expensive license you can achieve and keep the rest as liquidity.
Your network would do the rest for you either you'll have a call A bank license issued in any major country or a license granted in Vanuatu.
If the answer is no....well, you better start thinking about a plan B and eventually be supported by somebody, law firm but not necessarily even though at the end they'll be needed, that knows the "how to" in few jurisdictions where your dream can become reality.
Remember....everybody, nowaday, is looking for crypto friendly banks or an exchange that can guarantee liquidity between crypto and fiat.
Succeeding in this goal, means tons of money!!
Something is doable by using the blockchain and can become a REALLY interesting project for a lot of reason.
But again, you and your advisors should know where to put the hands.
Should you be REAL, as a base for discussions, and should your interest be 100% in this project, contact me if you want.
We don't have those bitcoin you have but we know the "how to".
But please...don't waste your and my time...no need for both of us.
Only suggestion, move before you treasure would deplets as a consequence of value depreciation.
Best wishes

how do you plan to put data on blockchain ?