The assumption doing the most work here is that a signed purchase agreement in a supervised probate creates the same bilateral obligation it would in an ordinary sale. It does not, and that is the core of your exposure.
In court-confirmed probate sales, the personal representative's authority to bind the estate is typically conditional. They can accept a deposit and execute a contract, but that contract is subject to the court's approval. The confirmation hearing is where the sale actually gets made. Another buyer can appear, bid over your price by the statutory overbid increment, and the court can confirm to them instead. Your signed agreement does not give you a priority position at that hearing. It gives you the right to be the nominated buyer going in, which is meaningfully different.
On the $5,000: whether it comes back to you if you are overbid depends on how the purchase agreement is written and whether Ohio's probate code or local Cuyahoga County practice governs refund of the deposit in that scenario. That is not a general answer I can give you with confidence, and the estate attorney's "held in good faith" language is not a substitute for a written refund provision in the contract itself. Go back to the signed agreement and find out whether it contains a deposit refund clause triggered by court non-confirmation. If it does not, you want that clarified in writing before the hearing, and that answer comes from an Ohio probate attorney you have retained directly, not the estate's counsel.
The risk your title rep flagged is real. The estate's attorney represents the estate, not you.
Two practical things worth confirming now: whether you have the right to appear and bid at the confirmation hearing yourself, and whether Ohio's code specifies a minimum overbid threshold, because that number determines how much protection your contract price actually offers you in the room.
What does your purchase agreement say specifically about deposit disposition if the court does not confirm?