I am completely indifferent to Mello Roos and HOA fees. They just mechanically reduce the value of the property by their discounted present value.
A quick way to estimate is to multiply the annual amount by 20, and consider that the discount in property price over a no HOA or Mello SFH. You can make a case that 15 or 25 are better multipliers, but I think 20 is reasonable.
If people really cared that much about avoiding HOAs, the builder could pre-fund it and raise the purchase price. But I don’t think they actually care and I don’t think you should care other than doing a quick NPV mental adjustment.