account_peppol has an external dependency on (the python package) 'phonenumbers' (https://github.com/odoo/odoo/blob/18.0/addons/account_peppol/__manifest__.py#L23), account_edi_proxy_client has an external dependency on (the python package) 'cryptography' (https://github.com/odoo/odoo/blob/18.0/addons/account_edi_proxy_client/__manifest__.py#L16). Now, usually Odoo should tell you upon installation that an external dependency is not met. But without further details, i.e. a log output from the exact time of trying to install the modules, not much can be told.

I'd suggest you try to install phonenumbers and cryptography, restart your server and then re-try to install 'account' from the UI.

To do so, run

python -m pip install phonenumbers
python -m pip install cryptography

Note that whether it is 'python', 'python3' or anything else depends on your setup. In case you're running a virtual python environment, switch to it first (also depends on your setup).

After that, restart the Odoo server and try to install account again.