Confirmed that bpo-42500 fixes this traceback, in commit 4e7a69bdb6 

Parent commit:

user@obsidian ~/t/f/cpython (master)> git checkout  93a0ef7
Note: switching to '93a0ef7'.
HEAD is now at 93a0ef7647 Correct return type in Modules/_ssl.c::sslmodule_legacy (GH-23609)

user@obsidian ~/t/f/cpython ((93a0ef76…))> ../test.sh
+ make distclean
+ CFLAGS=-O0
+ ./configure --prefix=/home/user/prefix --exec-prefix=/home/user/prefix --cache-file=../config.cache --with-pydebug --without-ensurepip
+ CFLAGS=-O0
+ make -j8 install
/home/user/cpython/Lib/runpy.py:111: PendingDeprecationWarning: lib2to3 package is deprecated and may not be able to parse Python 3.10+
  __import__(pkg_name)
/home/user/cpython/Lib/runpy.py:111: PendingDeprecationWarning: lib2to3 package is deprecated and may not be able to parse Python 3.10+
  __import__(pkg_name)
++ realpath /home/user/prefix/include/python3.10d/
+ INCLUDE_DIR=/home/user/prefix/include/python3.10d
+ set +e
+ PYTHONHOME=/home/user/prefix
+ /home/user/prefix/bin/python3 ../test.py
NoneType: None
...
NoneType: None
Fatal Python error: _Py_CheckRecursiveCall: Cannot recover from stack overflow.
Python runtime state: initialized

Current thread 0x00007f483d4bd740 (most recent call first):
  File "/home/user/prefix/lib/python3.10/traceback.py", line 165 in _some_str
  File "/home/user/prefix/lib/python3.10/traceback.py", line 524 in __init__
  File "/home/user/prefix/lib/python3.10/traceback.py", line 113 in print_exception
  File "/home/user/prefix/lib/python3.10/traceback.py", line 173 in print_exc
  File "/home/user/cpython/../test.py", line 4 in foo
  ...
../test.sh: line 33: 50081 Aborted                 (core dumped) PYTHONHOME=$PREFIX $EPREFIX/bin/python3 ../test.py
+ [[ 134 -eq 139 ]]
+ exit 0

After fix merged:

user@obsidian ~/t/f/cpython ((93a0ef76…)) [1]> git checkout 4e7a69bdb6
Previous HEAD position was 93a0ef7647 Correct return type in Modules/_ssl.c::sslmodule_legacy (GH-23609)
HEAD is now at 4e7a69bdb6 bpo-42500: Fix recursion in or after except (GH-23568)
user@obsidian ~/t/f/cpython ((4e7a69bd…))> ../test.sh
+ make distclean
+ CFLAGS=-O0
+ ./configure --prefix=/home/user/prefix --exec-prefix=/home/user/prefix --cache-file=../config.cache --with-pydebug --without-ensurepip
+ CFLAGS=-O0
+ make -j8 install
/home/user/cpython/Lib/runpy.py:111: PendingDeprecationWarning: lib2to3 package is deprecated and may not be able to parse Python 3.10+
  __import__(pkg_name)
/home/user/cpython/Lib/runpy.py:111: PendingDeprecationWarning: lib2to3 package is deprecated and may not be able to parse Python 3.10+
  __import__(pkg_name)
++ realpath /home/user/prefix/include/python3.10d/
+ INCLUDE_DIR=/home/user/prefix/include/python3.10d
+ set +e
+ PYTHONHOME=/home/user/prefix
+ /home/user/prefix/bin/python3 ../test.py
NoneType: None
...
NoneType: None
Traceback (most recent call last):
  File "/home/user/prefix/lib/python3.10/traceback.py", line 165, in _some_str
    return str(value)
RecursionError: maximum recursion depth exceeded while calling a Python object

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/user/cpython/../test.py", line 7, in <module>
    foo()
  File "/home/user/cpython/../test.py", line 5, in foo
    foo() 
  File "/home/user/cpython/../test.py", line 5, in foo
    foo() 
  File "/home/user/cpython/../test.py", line 5, in foo
    foo() 
  [Previous line repeated 989 more times]
  File "/home/user/cpython/../test.py", line 4, in foo
    traceback.print_exc()
  File "/home/user/prefix/lib/python3.10/traceback.py", line 173, in print_exc
    print_exception(*sys.exc_info(), limit=limit, file=file, chain=chain)
  File "/home/user/prefix/lib/python3.10/traceback.py", line 113, in print_exception
    for line in TracebackException(
  File "/home/user/prefix/lib/python3.10/traceback.py", line 632, in format
    yield from self.format_exception_only()
  File "/home/user/prefix/lib/python3.10/traceback.py", line 580, in format_exception_only
    yield _format_final_exc_line(stype, self._str)
  File "/home/user/prefix/lib/python3.10/traceback.py", line 156, in _format_final_exc_line
    valuestr = _some_str(value)
  File "/home/user/prefix/lib/python3.10/traceback.py", line 167, in _some_str
    return '<unprintable %s object>' % type(value).__name__
RecursionError: maximum recursion depth exceeded while calling a Python object
+ [[ 1 -eq 139 ]]
+ exit 0