Custom pop-up chars selection in letters and numbers

[610019610]

Hello!

I found out Heliboard offers a lot of customization options for editing the symbols layer. I like to write a lot of notes heavily using uncommon Unicode symbols (arrows, bullets, box drawing lines, math operators etc...) and glyphs variants (italic, script, double-struck, circled, superscript or subscript etc...), so relying on a custom keyboard is a very handy (other solutions like copy-pasting around from an Unicode map or using markdown languages like LaTex are very unconfortable and slow on mobile).

Until I edit the symbols layer, even deeply, everything works well (I really enjoyed it), however I never figure out a way to customize pop-ups of the QWERTY layer and of the numbers row.
For example I would like to select chars like 𝒂, 𝛼, 𝕒, ⓐ and ª when long-pressing on "a", or find characters like 𝟙, ₁, and ① on "1"; I also would like to put glyphs like … or ∙ at dot key aside the spacebar.
I cannot do that. I can just expand the viable diacritics and change the priority of their order.

I even tried to make a custom layout (as some posts found in Google searches suggest), but it doesn't work (maybe in older versions did it? Is it now unsupported or bugged?). Also honestly I don't want to mess up the basic QWERTY layout. I just want a broader selection in pop-ups.
I figured out a walkaround, using the symbols layer for those chars as well, but that trick looks as slighty unconsistent and unconventional from my point of view.

Please help me or let developers known about those issues. Thanks in advance.

Edit: I tried to make a custom layout copying the basic QWERTY setup and adding further characters as pop-up choices. This solution works better, but there are some issues (and maybe some bugs):

• I cannot deactivate the numbers row anymore, or in the symbols layer the top row of symbols will disappears (replaced by the default numbers row);
• If I want to make a custom number row, I could add a row with number in the QWERTY layer, but there I would find two numbers rows then (due to the issue I mentioned previously); That makes the keyboard looks weird;
• I cannot differentiate the pop-ups for small letters and the ones for capital characters: I have to implement a mixed bag of choices for each letter, which really limit my freedom (due to the hard cap of 20 choices, and due to the keeping many slots for the diacritics I need... both small and capital versions too, eating a lot of spots considering the whole situation.