GC-intensive benchmarks in Scheme

Dear Guile users.

I am looking for GC-oriented benchmarks, preferably portable Scheme code.

Why am I asking?
I am investigating a regression in GC time (bdw-gc) for many days,
but my application seems to be too complex for me to unterstand the cause:-)
Hence I am looking for simpler code that can reproduce the issue.
Currently in my (too complex) "benchmark" application,
the GC collects 70 GB collected in 200 collections.
The simple benchmark(s) I am looking for can be smaller, but not too much.

It seems to be caused by stepping from gcc-11 (or older) to gcc-12 (or newer),
but only for the x32 ABI - https://en.wikipedia.org/wiki/X32_ABI - so far.

Greetings
Sven