Firewall software will go through the list of incoming/outgoing rules top down and apply the first matching rule.
Hence, in case the first rule ufw finds is the default rule: deny any incoming and outgoing traffic, it will do so.
Trying to soften this rule later on will not have any effect.
I am afraid you will have to consult the usfw manpages in order to find out how to make sure that the rules are created and stored in this order:
80 ALLOW IN Anywhere
443 ALLOW IN Anywhere
80 ALLOW IN Anywhere (v6)
443 ALLOW IN Anywhere (v6)
reject any other requests
Yet, I am not sure whether blocking absolutely all outgoing packages is really what you want and need.
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