The real unique aspects of how it was made - COVID - would make it more expensive. Transport, accommodation, logistics.
There's a lot of expensive camera gear on site, lots of speaking roles, lots of effects and stunts. Lots of crew.
Depending on the number of people on set they could've burned through almost a million a week just in payroll.
Cheap movies on tight budgets generally do not have so many camera cranes out on location.
I've seen worse VFX in movies with three times the suggested budget. The fact they had money to burn on cosmetic "enhancements" on the suit despite the fact it looked just fine kind of speak to them having disposable income.
I look at the behind the scenes and I see a loooot of money. Which absolutely they could've got things affordably - like I said, maybe it was cheaper - but I don't flinch when someone says it cost $65m. I buy it.
There's also an interesting question I should've put in the ask Dan thread - did going direct to streaming affect cast and crew pay? Usually there would be percentages and residuals. Key cast and crew may have been paid extra to account for lack of ticket revenue.
I think the movie looks cheap in places, but the production does not look cheap to me.