If you want to open and edit files that are on your Nextcloud with apps on your PC that do not natively support WebDAV, you will have to use some sort of client that stores the files locally before they can be opened with the corresponding app. And with the newest version of the Nextcloud Client you get VirtualDrive, so only the files you actually double-click, are getting downloaded to the PC.
If you don’t like how the Nextcloud client handles this and how it integrates with the Windows Explorer and the native WebDAV client in Windows also doesn’t work well enough for you, there’s no other way but to use a 3rd party client. MountainDuck is one of the more popular ones for this purpose. But in principle all these clients work in a similar way. And this applies more or less to all of the “cloud storage” providers and their corresponding clients. It doesn’t matter if you use Google Drive, Dropbox, OneDrive, SharePoint etc. If you don’t like that and want to have classic drive letters and network shares, it’s probably best to use a SAMBA server. But then of course you lose all the advantages that a solution like Nextcloud offers.
And honestly… What’s the big deal having a folder instead of a drive letter? You can add this folder as a favorite to the top left side of the Windows Explorer. Users then have to click on this folder icon instead of clicking on a drive icon. That should be doable, shouldn’t it?