I suggest that we just port stuff there to GAP4.
It is a nontrivial amount of work, but some of it is already done by
your humble servant and others, see e.g.
https://github.com/gap-system/ve (something that I plan to turn into a proper GAP4 package,
which is easy, as the porting to new GMP is done) and
https://github.com/dimpase/anusq (which even has a crude GAP4 interface now, and the original
author of anusq has promised to finish this off)
This package as it is is a swarm of bugs, as e.g. some parts of it rely on very outdated GMP, some
of it have GAP bugs fixed in GAP4, etc etc.
Cheers,
Dima