Hi
Before creating Gestinux, I have developped softwares for points of sale or similar needs, with Access alone, or with Delphi+Access, some of them working mainly during the night.
We have had data loss, due to crash, because Access is not client-server and is not reliable enough when power supply or network is down. Not often, less than with Paradox, but once a year is even too much.
And also we have had several times to make changes in the hardware and in the software, and to buy new licences, because of evolutions of Windows, Access, Delphi requiring new drivers, more memory, et c...
MariaDb or PostgreSQL are certainly more reliable than Access, and we have had never any data loss for years, and it is possible (and necessary) to schedule a very quick on-line backup.
But developing a new software can be time consuming, far more than you can preview. Sharing an existing free software like Gestinux is indeed a good option. You could of course improve it to suit your needs.