If you're appraisal price didn't/won't meet the 75%-80% LTV mark.

In early 2021 the house was appraised at approximately $345,000.

Listed at $244k and is under contract for $255k and appraised for total offer price.

I sold it in 2020 for a loss based on the appraisal we got in 2017.

With this in mind you need to be prepared to refinance into a permanent/long-term loan based on appraised value. 

If the Borrower moves back to the original area, the Borrower is not required to live in the original house and may obtain a new FHA-insured Mortgage on a new Principal Residence, provided the relocation meets the two requirements above.A Borrower may be eligible for another house with an FHA-insured Mortgage if the Borrower provides satisfactory evidence that:• the Borrower has had an increase in legal dependents and the Property now fails to meet family needs; and• the Loan-to-Value (LTV) ratio on the current Principal Residence is equal to or less than 75% or is paid down to that amount, based on the outstanding Mortgage balance and a current residential appraisal.

You think your home will appraise for me in the future (Appraisal/Renovations)2.

Will there be any issues if someone purchases a home below what the estate appraiser value home for?

First value during appraisal or selling, with a garage ups (no garage decreases value)  the value of a home as opposed to not having garage.

Estimate taxes directly with new purchase price from county appraiser website.Don't count on rentometer to give you an accurate rent estimate.