I guess the indention sizer thing knows how the formater works and adjusts accordingly. I can't imagine it would be too much of a problem.

Iirc Jetbrain IDEs has a feature called dynamic tabs/space (or something like that) which uses exclusively tabs until it needs to align something and a tab doesn't fit, so it uses a few spaces instead.

Maybe alignment more for the righthand side of assignments. If you have a block of variables with different name lengths, or within a constructor / function call.

All parsers ignore a shitload of whitespace already. Just compare unformatted code, COMPLETELY unformatted code, code without character returns, and it'll become obvious how any given language is interpreted around whitespace.

Also fun to see just how infrequent a semicolon is 'actually' needed to tell when the end of a statement is here.

Then you use the variable width space for code indentation, then, when you're at the code indentation level, you'd switch to spaces for alignment. If the IDE special cased all space characters at the start of the line you wouldn't have that flexibility. You could also easily create a linter that ensured that the variable width space always has the correct indentation level, and ignore the standard space characters after it.