Choosing a DBMS for biometric analysis?

Question

Database

Good day, for a scientific project, you need to implement a biometric voice analysis.
It is necessary to create a client application that would allow the user to fill in part of the data in an organized form (for example: gender, age, weight), a large number of unique factors and the possibilities of their combinations (for example, "cross-country skiing" + "swimming"), part of the data is filled in free form (e.g. diet, lifestyle).
The data is filled in 1 time. Data may change over time, so it is necessary to provide for the possibility of changing them. Next, the user's voice is recorded from the microphone (including those built into Android \ iOS), and the data + voice is sent to the server in encrypted form.
On the server:
1) Data in text form is added to the database + the name of the audio file is added.
2) The voice passes through the analyzer, the assumptions are added to the database.
3) Voice + data pass through the analyzer, it learns and compares with the assumption, the result of the reconciliation is written to the database.
4) After that, the audio files are encrypted.
5) With the release of a new version of the analyzer, all data is analyzed again to improve accuracy.
The load for the next two or three years will not be very large, up to 10,000 - 45,000 incoming recordings with voice per day at best.
The analyzer will be made on the basis of the received samples, probably with the participation of the OpenSource community.
In the future, it is planned to localize the client application into other languages.
What database \solutions can you advise to solve this issue?
It is also necessary, when developing the server side, to implement this rule from the Federal Law "On the Protection of Personal Data":
"1. When processing personal data, the operator is obliged to take the necessary organizational and technical measures, including the use of encryption (cryptographic) means, to protect personal data from unauthorized or accidental access to them, destruction, modification, blocking, copying, distribution of personal data, as well as from other illegal actions.
What is the best way to achieve this? Hardware/software encryption or something in between?
If there is a desire or opportunity to participate in the development of such a solution, please write to the PS. It will give a lot of scientific potential and maybe later it can be commercialized through technical support or in another way.
Thank you for your attention.