Need suggestions for early mailing list growth

I have a short story reader magnet published and going out to new subscribers.
I have another short story I hope to send to the list by mid-summer.
I hope to have my first book ready for sale by the end of 2026.

I have sent out newsletters every two weeks since February (just sent #9 last week).
I initially seed my list via personal contacts, general Facebook message, etc. (40-50)
I have been using BookFunnel group promos to grow that list and it has helped grow my list to 192 (as of today).
The latest newsletter has 56.45% open rate, ~11.83% click rate, and 1.08% unsubscribe. (That has been the pattern the last few newsletters, but with slowly growing numbers)
I recently started publishing older newsletters as blog posts (8 week delay)

I am thankful for slow but steady growth using BookFunnel, but want to pursue other options as well since it seems to be drip-drip-drip.

I think I’m ready to look for newsletter swaps (Thriller / Wilderness Adventure), so started investigating using StoryOrigin today.

Any other near-term suggestions for me?
Any feedback on whether that growth rate is good or bad for an unpublished author?

Website: https://www.dougsjoquist.com
Blog: https://www.dougsjoquist.com/blog/