The new apt(8) high-level command, when run with the subcommand 'update', kindly suggests you run 'apt list --upgradable' when upgrades are available. Let's automate that :)

apt-update+list.sh

#!/usr/bin/env bash

# Run 'apt update' and print every (nonempty) line except the last one with the suggestion to run
# 'apt list --upgradable'.
# In fact we do as suggested instead. :)
apt update 2>&1 | \
  awk '
  BEGIN { eatnextemptyline = 0 }
  /^$/ { if (eatnextemptyline) { eatnextemptyline = 0; next } }
  /WARNING: apt does not have a stable CLI interface. Use with caution in scripts./ { eatnextemptyline = 1; next }
  /apt list --upgradable/ {
    print "It seems the following packages can be upgraded:";
    system("apt list --upgradable");
    next;
  }
  { print $0; }
  '