16bit Windows software will not work natively on 64bit Windows. However this isn't a recent change, this is happening since the introduction of 64bit Windows and consumers started getting 64bit Windows already for more than a decade ago.
There are solutions, however.
For 16bit Windows software you can try https://github.com/otya128/winevdm which provides 16bit emulation and pass-through of Windows API calls to a mix of Wine and Win32 native calls. It isn't perfect but it can run a lot of Windows 3.x software. You can either drag-drop the executable on the emulator's exe file or use the supplied registry files to install it system-wide.
DOS software tends to work fine under DOSBox or vDos (a DOSBox fork explicitly made for text-based DOS applications).
Now i'm not saying you cannot find cases where stuff do not work, but in my experience most stuff work out of the box or with little tweaks.
