Has the maintainer looked at fair source? [0] I believe it's superior to source-available (and open core), because it eventually becomes fully open source under DOSP [1], which is great for free and paid users, especially for a blog platform like Bear. There's an FCL [2] fair source license, which aligns pretty well with their current Bear Blog License (namely the non-compete and license key bits from the ELv2). All in all, the term "source-available" is pretty meaningless, because there are too many variables. Fair source tries to tighten that up.
It also aligns quite well with Bear's manifesto [3]. Even if Bear PTY LTD ceases to exist, Bear won't. This can be codified under DOSP.
Disclaimer: I'm involved with fair source and helped write the FCL.
[0]: https://fair.io
[1]: https://opensource.org/dosp
[2]: https://fcl.dev