I have a similar trouble with feedback and I think it’s fairly common. I have 70 to 90 Patrons throughout the month and maybe 5 of them actually comment and a few others message me. Here’s the “trick” I’ve found to be very useful:
I use Patreon polls. For example, you might ask how they find you. You could also ask what was there favorite thing you published this month.
I’m a model and I use a poll each month in about the last week to allow them to vote on which galleries to include the next month. Usually I let them vote for one or two and then I pick the other one or two.
I get much more feedback on polls than I do if I just ask. I looked back and I usually get 20 to 30 responses on those polls.
Bonus Tip: Make sure if you let them vote, that you only include options that you are okay with winning. So don’t end up making too much work for yourself or offering something you can’t do.
Now moving on…
I’d suggest you poll your Patrons on how they found you. Include your top social platforms and be sure to include an “Other, please let me know in the comments.” Even if you only get one response, you can use that information to know where you might focus your promotional efforts.
Here are some promotional ideas for social media to help you build your audience.
Instagram
Post short clips of your videos.
You can also post photos of past merch you’ve sent Patrons (or mockups of the designs) occasionally.
Interact with others there too. You might even find other musicians who can inspire you with how they use the platform.
IGTV might be useful for you too, especially now that those videos are inserted into the feed.
YouTube
I would stick with the occasional full piece/song or quick tips. Not as in depth as you offer on Patreon, but something to get people interested.
Twitter
Similar to Instagram. You can share short clips, photos, etc. Find the hashtags and follow others. I’ve found that following people who interact with other similar accounts to be really useful, many times they’ll follow you back.
Twitter is a little different than the others, but it’s very useful. You can be a bit more free with it too. I throw in personal stuff (like what I’m having for dinner or personal experiences) every so often and it goes over pretty well there.
For example, you could post things like “I just tried a new arrangement and boy was it tough! Who else is working on a new piece?” (But use the correct terms, I’m just kind of rolling with it right now)
There might be other music specific sites I’m not aware of or tips that other musicians can add in too. Mainly, I think you just need to grow your fanbase. 