“Lowball” offer on house being sold “as is” - how to proceed

My husband and I have been eyeing a house that’s been for sale for 185+ days in the neighborhood we currently live in. Comparable sized houses and lots have sold in the last year ranging from $1.5M to ~$900k depending on factors including whether or not the lot can be split (typically purchased by developers) and the condition of the home etc.

This house is being sold “as is” and was originally listed at $1.3m. We knew it was overpriced and after walking through with an inspector and some family in construction we estimated it needed between $200-$300k in work just to get it back to basics and weather proof/seal the house (new windows, updated electrical, new roof, repaired siding, refinish floors from dog pee, remove many layers of raccoon feces from attic, mold remediation, etc.). Does not include several other needs including kitchen renovation, AC installation, etc. that would be making the home more modern/comfortable. The house has been empty since last December when the owner was removed due to declining health and old age. A nephew is POA and his wife is acting as a real estate agent.

We were told no offer would be offensive so we offered $700k a few months ago. They countered with $1.2 and were not playing ball to get below $1M and so we left it knowing we didn’t really want to go above $800k and never raising our offer above $725k at the time.

Fast forward and as we expected the price has continued to lower and now it’s at ~$940k. Other homes in better condition with similar characteristics have sold for ~900 during that time. Our agent reached out to the seller again and was told that “all offers in the 700s have been rejected” and “we were in negotiations with an offer in the 800s that fell through due to financing”.

Their response is of course designed to encourage higher offers, but also gives away that they don’t expect to get their current list price. I think it remains possible to get the house for under $800 given the amount of work the house requires.

Interested in opinions about reaching back out with an offer of $750 with the intention of leaving room for negotiation up to $800k. Offensive? Should we wait for them to drop the price again as they typically do every month?

alternatively talk me out of this and say it’s a bad idea. We’ve become fixated on the house but also fixed on the idea of not overpaying for it.

Other notes:

• @$800k we could buy this house without selling our current home but it is our hope/intention to sell out existing home for ~$500k for better cash flow for new home repairs. but we have considered making our offer with no contingency for selling our current home.
• house is a ~1900 Victorian in a North East city suburb
• current home is also 100 years old and also required substantial renovation though not to the extent of the other house. We expect to DIY and contract out as we have with our current home.