Hey! First of all thank you for your kind words. 
Next, to answer some of your questions and requests:
It would be great if Bear could open to a specific note directly
Single note widget was born to do this! Just add it to your screen and then you can open the note you want with one tap. You can find more information and the instruction here.
the ability to create custom themes would be even better
Currently we don’t have plans to add this, but if you see any nice dark themes somewhere, let us know on forum and we will take into consideration for future themes!
More colours for the highlighter tool would be very helpful
It is on our todo list, check this post and let us know what you think! 
When writing dates in the Czech format (e.g., 18. 7. 2024), Bear automatically converts them into ordered lists.
Unfortunately number + . + space is the Markdown rule for ordered list. As a Markdown notes app we are unable to change this. That being said, you can use the escaping character backlash \ before the first . to disable it, like this: 18\. 7. 2024. In this way the dates won’t convert into ordered lists.
Tabs
Currently we don’t have plans to add tabs, but soon we will support the new window tilting feature on macOS Sequoia and hopefully it helps to easily organize multiple notes windows on Mac for you!
Merging cells
Unfortunately Markdown tables is very basic and within the rules we are unable to support advanced table features like merging cells. 
LaTeX
This is something we’d really like to support, but it is quite challenging and time consuming. There are a lot of things we need to consider from dependency management to performance concerns and compatibility. Currently this is not our top priority, but we will continue our research. 
Thank you again for your support, these are all great feedback and we are so grateful to have you in our community! Let us know if you have any other feedback or questions! 
