These are the relevant parts of your log:
In file included from /tmp/python-build.20210602162502.2268/Python-3.9.4/Modules/_cursesmodule.c:113:
./Include/py_curses.h:36:10: fatal error: curses.h: No such file or directory
36 | #include <curses.h>
| ^~~~~~~~~~
compilation terminated.
/tmp/python-build.20210602162502.2268/Python-3.9.4/Modules/_ctypes/_ctypes.c:107:10: fatal error: ffi.h: No such file or directory
107 | #include <ffi.h>
| ^~~~~~~
compilation terminated.
Python build finished successfully!
The necessary bits to build these optional modules were not found:
_bz2 _curses_panel _dbm
_gdbm _lzma _sqlite3
_tkinter _uuid zlib
To find the necessary bits, look in setup.py in detect_modules() for the module's name.
The following modules found by detect_modules() in setup.py, have been
built by the Makefile instead, as configured by the Setup files:
_abc atexit pwd
time
Failed to build these modules:
_ctypes _curses
Traceback (most recent call last):
File "<frozen zipimport>", line 520, in _get_decompress_func
ModuleNotFoundError: No module named 'zlib'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "<frozen zipimport>", line 568, in _get_data
File "<frozen zipimport>", line 523, in _get_decompress_func
zipimport.ZipImportError: can't decompress data; zlib not available
It looks like you’re missing the dependencies that pyenv requires for building python. Since you’re using Ubuntu, run the following:
sudo apt update
sudo apt install \
build-essential \
curl \
libbz2-dev \
libffi-dev \
liblzma-dev \
libncursesw5-dev \
libreadline-dev \
libsqlite3-dev \
libssl-dev \
libxml2-dev \
libxmlsec1-dev \
llvm \
make \
tk-dev \
wget \
xz-utils \
zlib1g-dev
Then try again.