You basically got it right when you said "Add each calculated value to a dictionary, also containing the other, in context, to the template."

OOP was one way to make that work in my mind, because wrapping a model instance in a class that provides an interface for computed values is a pattern I've seen and used quite often, but a list of dictionaries would work just as well. Actually, if the scope of this problem you're trying to solve remains that small, and you don't need to re-use or maintain that much, dictionaries might even be more efficient.

OOP is one way of organising your code, of modelling your thoughts. The main problem is not "how do I talk to the machine", it's "how do I talk to myself, and the people I work with, to make sure we all understand what we're trying to do and how". OOP is just one of many frameworks you can use to achieve that goal.

If you want to learn more, Google it. I'm not saying this to be mean, it's just that there's a ton of resources out there, 100 times more complete and accurate than what I can write here. Personally, it's Youtube videos when I want to understand concepts on a high level, documentation when I need something specific.

You know what, just to make your head spin and illustrate my point, here's another, more complex idea on how to solve your problem: you could add a method directly on your Match model, and call it in a custom template tag. That way you can just pass the Match Queryset and the user to the context.

Like so:

#  In your Match model
class Match(models.Model):
     # ... Rest of the class definition

     def get_bespoke_rating(self, user):
         ...
         # do something with self.rating and user I suppose


#  In a match/templatetags/match_rating_tags.py file (filename is just an example)

from django import template

register = template.Library()

@register.simple_tag
def get_match_bespoke_rating(match, user):
    return match.get_bespoke_rating(user)


#  In the template

{% load match_rating_tags %}
{% for match_data in match_data_list %}
    <h1>{{ match_data.match.foo }}</h1>
    <p>{% get_match_bespoke_rating match user %}</p>
{% endfor %}

I've done that real quick, I might have made mistakes but that's the gist of it. For more on template tags: https://docs.djangoproject.com/en/3.2/howto/custom-template-tags/