So I have a couple of suggestions.
First, I would highly recommend staying in the centre near the river (1st Arrondisement or on the other side of the river - 6th / 5th I think). You might get cheaper hotels further out but being able to walk around the centre is much better. Staying in the 1st puts you walking distance from the Louvre, Place de la Concord, Arc de Triomphe, Notre Dame, Eiffel Tower etc etc
Second, there are a lot of 3* hotels around that area that are fine - family run type of places or small chains. They will tend to have very limited restaurant / bar services but you won't need that anyway. The rooms are fine but not huge (generally true of Paris hotels anyway). Once you go to higher * hotels, the cost goes up exponentially.
Places I have stayed around here that you might want to check out....
Hotel Du Lion D'Or -
https://www.hotelduliondor.com/en/
Hotel Montpensier -
https://www.hotelmontpensierparis.com/
Accor hotels have a range of hotels in this area - they have budget hotel brands (IBIS / Mercure) and medium budget brands (Novotel / Adagio) - but they are all decent and clean. There are a number in the areas I mentioned
I've stayed in Best Westerns in Paris before and they have a few around the centre - I think the one I stayed in was Best Western Gaillon Opera - again they are decent, clean and pretty reasonable for the area.
https://www.hotel-paris-gaillon-opera.com/en/ (Best Western has about 4 or 5 within 15 mins of this one)
Most of my trips have been rugby related - so we weren't looking to hang out all day in the hotel. But at the same time we weren't looking for kips - they were decent enough but central