Just a note that JUCE is now free for indie developers if your yearly revenue is less than $50K per year. It just adds a JUCE logo for a few seconds the first time your plugin window opens.
Also, it looks like JUCE is available for a one-off fee, if you don't like the monthly subscription. $700 once on an annual revenue of $200K seems reasonable, especially since there's the free-with-splashscreen tier to help you earn that first $700.
Or as an alternative DPF https://github.com/DISTRHO/DPF which at least supports JACK and LV2 (the pull request for it for JUCE has gone unmerged for years :( and no additional license restrictions
If you don't like that, GPL is still an option.