Apache2 conditional section based on port
Solution 1:
Yes, starting from Apache 2.4, you can use
<If "%{HTTPS} == 'on'">
# HTTPS-specific configuration here
</If>
in your configuration file.
Many other expressions inside the <If "expression"> bracket are also supported, e.g. actually checking for a specific port, as you suggested. For more details see the Apache docs.
However, keep in mind that some directives will not work within an <If> clause. Check for the allowed contexts of a directive, where <If> counts as a directory context (like <Directory>).