DNG is supported by most open source RAW developers, e.g. Darktable. I'm assuming you've had some issue more subtle than inability to find a program roughly equivalent to Lightroom that has general support for the format, but you may need to elaborate if you want useful responses.
To be honest, I haven't yet put any serious effort into figuring out how to abandon Lightroom. At most... I just did a few searches for a couple of programs I already knew about and looked at whether they supported DNG. Most comments I found online sounded negative (but again, my research was too superficial). I didn't even know Darktable existed for example!
I am a very light Lightroom user. I have thousands of pictures, but mostly use Lightroom to categorize them and do some trivial edits here and there. The pictures are already organized in a tree structure with sidecar XMP (?) metadata files, so I don't think the LR catalog has a ton of information I care about anyway?
I'd be nice to have a pure file-system based catalog that separates edits from originals in some way, and that keeps photo metadata attached to the photos themselves.
But I guess my question remains: is it a good idea to continue "investing" into DNG by converting new photos into it, or is it better to "stop the bleeding"? Because from what I have read before, this format didn't seem too well-supported outside of Adobe apps...
Darktable and RawTherapee are fairly Lightroom-like (but different enough that you shouldn't be surprised when things are, well, different), but Filmulator might actually be the best fit for your preferences.
Regardless, the best way to get an answer to your question about DNG is probably to try some of these programs with your files and see if you encounter any problems. DNG is typically better supported than camera-specific raw formats.
I'd say to keep adding to your DNG collection as is, because if you switch and you need to convert, 1-2% extra images won't hurt. RawTherapee is also a RAW image processing software that can help, instead of Darkroom, or maybe just to convert your DNGs to whatever other raw format Darkroom likes.
