> However, as a downside our lookbehinds do not support containing capture groups which are a feature allowing to extract a substring that matched a part of the regex pattern.

I wonder in what situation someone would even be tempted to put a capture group into a lookbehind expression, except unintentionally by using () instead of (?:) for grouping. Maybe in an attempt to obtain capture groups from overlapping matches? But even in that case, lookaheads would be clearer, when available.