Hello,
(I hope I'm not posting in duplicate)

<IMHO>
I also think there is a problem.

Companies that have a chance to make money on the Internet, use database servers, and therefore databases under Linux servers.
Microsoft has its Azure Cloud on Linux server. SQL-server is installed on Linux servers, such as mySQL, Oracle, etc.
The only tool I can use to create a *.fdb is FlameRobin (an "abandonware"); Firebird being used by the Delphi Lazarus developer community, the fact that it is written in C\C++ instead of Pascal can, perhaps, partly explain this fact.
As the Firebird organization is constantly creating new combinatorial features, and this is to their credit. But without a tool with a graphical interface under Linux to understand these features, is it really used...?

For information, under Lazarus, there are "bounties": globally, people who are involved in a problem say how much they put in a common pot, for a writing of a feature. Inspired by this idea, is it not conceivable that Firebird would partner with a specialized Firebird metadata management editor, via a kind of crowdfunding, to create or port a completely open-source or semi-open-source tool for creating or managing Firebird databases running under Linux too (I would point out, that I have done some tests of database creation under Wine: for me, the database created cannot be used by a Linux application because when I want to open it, I get the message "onsupported on-disk structure for file /hom/Me/.software/test_only_one_tbl.fdb; found: 11.2, support 12.0"; so, I'm stuck with FlameRobin: how long will it work?; and I couldn't install Red Expert), with an advantage for those who subscribe (everything is imaginable).

</IMHO>

my 2 cents.
Best regards.